Roll recipe dependencies (nontrivial).

scripts/slave/recipe_modules/auto_bisect/example.expected/basic_bisect_script.json

 [
   {
     "cmd": [
       "git",
       "update-ref",
       "refs/heads/master",
       "refs/remotes/origin/master"
     ],
     "cwd": "[TMP_BASE]/fake_checkout_tmp_1",
     "name": "git update-ref"
@@ skipping 736 matching lines @@
       "--git-cache-dir",
       "[GIT_CACHE]",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@HEAD",
       "--output_manifest"
     ],
     "env": {
       "GCLIENT_KILL_GIT_FETCH_AFTER": "1200",
-      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
+      "PATH": "RECIPE_PACKAGE_REPO[depot_tools]:%(PATH)s"
     },
     "name": "bot_update",
     "~followup_annotations": [
       "@@@STEP_TEXT@Some step text@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"did_run\": true, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"fixed_revisions\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"src\": \"HEAD\"@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"manifest\": {@@@",
@@ skipping 273 matching lines @@
       "{\"bisect_config\": {\"bad_revision\": \"314017\", \"bug_id\": \"-1\", \"builder_host\": \"master4.golo.chromium.org\", \"builder_port\": \"8341\", \"bypass_stats_check\": \"True\", \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"dummy_builds\": \"True\", \"dummy_job_names\": \"True\", \"dummy_tests\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"linux_perf_tester\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"buildnumber\": 123456, \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}"
     ],
     "name": "Running Bisection"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]