chromium_tests: fix crash in deapply_patch on got_webkit_revision

scripts/slave/recipes/run_presubmit.expected/fake_svn_master.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "experimental.svn",
       "--builder",
       "chromium_presubmit",
       "--slave",
       "TestSlavename",
       "--spec",
       "cache_dir = None\nsolutions = [{'custom_vars': {'googlecode_url': 'svn://svn-mirror.golo.chromium.org/%s', 'nacl_trunk': 'svn://svn-mirror.golo.chromium.org/native_client/trunk', 'sourceforge_url': 'svn://svn-mirror.golo.chromium.org/%(repo)s', 'webkit_trunk': 'svn://svn-mirror.golo.chromium.org/blink/trunk'}, 'deps_file': 'DEPS', 'managed': True, 'name': 'src', 'url': 'svn://svn-mirror.golo.chromium.org/chrome/trunk/src'}]",
       "--root",
       "src",
       "--revision_mapping_file",
-      "{\"src\": \"got_revision\", \"src/native_client\": \"got_nacl_revision\", \"src/third_party/WebKit\": \"got_webkit_revision\", \"src/third_party/webrtc\": \"got_webrtc_revision\", \"src/tools/swarming_client\": \"got_swarming_client_revision\", \"src/v8\": \"got_v8_revision\"}",
+      "{\"src\": \"got_revision\", \"src/native_client\": \"got_nacl_revision\", \"src/third_party/webrtc\": \"got_webrtc_revision\", \"src/tools/swarming_client\": \"got_swarming_client_revision\", \"src/v8\": \"got_v8_revision\"}",
       "--issue",
       "12853011",
       "--patchset",
       "1",
       "--rietveld_server",
       "https://codereview.chromium.org",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@HEAD",
@@ skipping 13 matching lines @@
       "@@@STEP_LOG_LINE@json.output@    \"got_nacl_revision_git\": \"d998e125e8253980d76e269b7982aeeefc1b9b50\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_revision\": 170242, @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_revision_cp\": \"refs/heads/master@{#170242}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_revision_git\": \"f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_swarming_client_revision\": 276089, @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_swarming_client_revision_cp\": \"refs/heads/master@{#276089}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_swarming_client_revision_git\": \"a0ee5d99f1d4b38ddaa4c759c837980b63b99566\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_v8_revision\": 43426, @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_v8_revision_cp\": \"refs/heads/master@{#43426}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_v8_revision_git\": \"801ada225ddc271c132c3a35f03975671d43e399\", @@@",
-      "@@@STEP_LOG_LINE@json.output@    \"got_webkit_revision\": 124383, @@@",
-      "@@@STEP_LOG_LINE@json.output@    \"got_webkit_revision_cp\": \"refs/heads/master@{#124383}\", @@@",
-      "@@@STEP_LOG_LINE@json.output@    \"got_webkit_revision_git\": \"5e2293dffc3cd07d37fbedea3b500f0eb650614d\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_webrtc_revision\": 120644, @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_webrtc_revision_cp\": \"refs/heads/master@{#120644}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_webrtc_revision_git\": \"0f90628433546e61d9268596da93418c623137f4\"@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"root\": \"src\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"step_text\": \"Some step text\"@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@",
       "@@@SET_BUILD_PROPERTY@got_nacl_revision@274981@@@",
-      "@@@SET_BUILD_PROPERTY@got_webkit_revision@124383@@@",
       "@@@SET_BUILD_PROPERTY@got_swarming_client_revision@276089@@@",
       "@@@SET_BUILD_PROPERTY@got_webrtc_revision@120644@@@",
       "@@@SET_BUILD_PROPERTY@got_revision@170242@@@",
       "@@@SET_BUILD_PROPERTY@got_nacl_revision_cp@\"refs/heads/master@{#274981}\"@@@",
-      "@@@SET_BUILD_PROPERTY@got_webkit_revision_cp@\"refs/heads/master@{#124383}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_v8_revision@43426@@@",
       "@@@SET_BUILD_PROPERTY@got_v8_revision_cp@\"refs/heads/master@{#43426}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_swarming_client_revision_cp@\"refs/heads/master@{#276089}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_nacl_revision_git@\"d998e125e8253980d76e269b7982aeeefc1b9b50\"@@@",
       "@@@SET_BUILD_PROPERTY@got_webrtc_revision_cp@\"refs/heads/master@{#120644}\"@@@",
-      "@@@SET_BUILD_PROPERTY@got_webkit_revision_git@\"5e2293dffc3cd07d37fbedea3b500f0eb650614d\"@@@",
       "@@@SET_BUILD_PROPERTY@got_revision_cp@\"refs/heads/master@{#170242}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_v8_revision_git@\"801ada225ddc271c132c3a35f03975671d43e399\"@@@",
       "@@@SET_BUILD_PROPERTY@got_webrtc_revision_git@\"0f90628433546e61d9268596da93418c623137f4\"@@@",
       "@@@SET_BUILD_PROPERTY@got_swarming_client_revision_git@\"a0ee5d99f1d4b38ddaa4c759c837980b63b99566\"@@@",
       "@@@SET_BUILD_PROPERTY@got_revision_git@\"f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9\"@@@"
     ]
   },
   {
     "cmd": [
       "git",
@@ skipping 47 matching lines @@
       "@@@STEP_LOG_LINE@json.output@    \"chromium_presubmit\", @@@",
       "@@@STEP_LOG_LINE@json.output@    [@@@",
       "@@@STEP_LOG_LINE@json.output@      \"compile\"@@@",
       "@@@STEP_LOG_LINE@json.output@    ]@@@",
       "@@@STEP_LOG_LINE@json.output@  ]@@@",
       "@@@STEP_LOG_LINE@json.output@]@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   }
 ]