Roll recipe dependencies (nontrivial).

scripts/slave/recipes/bisection/desktop_bisect.expected/basic_perf_tryjob_with_revisions.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_perf_bisect",
       "511"
     ],
     "name": "makedirs checkout path",
@@ skipping 31 matching lines @@
       "https://codereview.chromium.org",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@HEAD",
       "--output_manifest"
     ],
     "cwd": "[BUILDER_CACHE]/linux_perf_bisect",
     "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 286 matching lines @@
       "--rietveld_server",
       "https://codereview.chromium.org",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@bad49c331def2a3bbf3ddd0096eb51551155",
       "--output_manifest"
     ],
     "cwd": "[BUILDER_CACHE]/linux_perf_bisect",
     "env": {
-      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
+      "PATH": "RECIPE_PACKAGE_REPO[depot_tools]:%(PATH)s"
     },
     "name": "bot_update (without patch) - bad49c331def2a3bbf3ddd0096eb51551155",
     "~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\": \"bad49c331def2a3bbf3ddd0096eb51551155\"@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"manifest\": {@@@",
@@ skipping 281 matching lines @@
       "--rietveld_server",
       "https://codereview.chromium.org",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@d49c331def2a3bbf3ddd0096eb51551155",
       "--output_manifest"
     ],
     "cwd": "[BUILDER_CACHE]/linux_perf_bisect",
     "env": {
-      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
+      "PATH": "RECIPE_PACKAGE_REPO[depot_tools]:%(PATH)s"
     },
     "name": "bot_update (without patch) - d49c331def2a3bbf3ddd0096eb51551155",
     "~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\": \"d49c331def2a3bbf3ddd0096eb51551155\"@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"manifest\": {@@@",
@@ skipping 199 matching lines @@
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]