Roll recipe dependencies (nontrivial).

scripts/slave/recipes/webrtc/standalone.expected/tryserver_webrtc_linux_swarming.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "\nimport sys, os\npath = sys.argv[1]\nmode = int(sys.argv[2])\nif not os.path.isdir(path):\n  if os.path.exists(path):\n    print \"%s exists but is not a dir\" % path\n    sys.exit(1)\n  os.makedirs(path, mode)\n",
       "[BUILDER_CACHE]/linux_swarming",
       "511"
     ],
     "name": "makedirs checkout path",
@@ skipping 92 matching lines @@
       "python",
       "-u",
       "RECIPE_MODULE[build::isolate]/resources/find_isolated_tests.py",
       "--build-dir",
       "[BUILDER_CACHE]/linux_swarming/src/out/Debug",
       "--clean-isolated-files"
     ],
     "name": "clean isolated files"
   },
   {
-    "cmd": [],
     "name": "ensure_goma"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::cipd]/resources/bootstrap.py",
       "--platform",
       "linux-amd64",
       "--dest-directory",
@@ skipping 2347 matching lines @@
       "@@@STEP_LOG_END@json.output@@@",
       "@@@STEP_LINK@shard #0 isolated out@blah@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]