Revert of depot_tools: add infra_paths recipe module for infra-specific paths

recipe_modules/bot_update/example.expected/trychange_oauth2.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "tryserver.chromium.linux",
       "--builder",
       "linux_rel",
       "--slave",
       "totallyaslave-c4",
       "--spec",
       "cache_dir = '[GIT_CACHE]'\nsolutions = [{'deps_file': '.DEPS.git', 'managed': True, 'name': 'src', 'url': 'svn://svn.chromium.org/chrome/trunk/src'}]",
       "--root",
       "src",
       "--revision_mapping_file",
       "{\"src\": \"got_cr_revision\"}",
       "--git-cache-dir",
       "[GIT_CACHE]",
       "--apply_issue_email_file",
-      "[ROOT]/b/build/site_config/.rietveld_client_email",
+      "[BUILD]/site_config/.rietveld_client_email",
       "--apply_issue_key_file",
-      "[ROOT]/b/build/site_config/.rietveld_secret_key",
+      "[BUILD]/site_config/.rietveld_secret_key",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@HEAD"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "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\"@@@",
@@ skipping 11 matching lines @@
       "@@@SET_BUILD_PROPERTY@got_cr_revision@\"f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9\"@@@",
       "@@@SET_BUILD_PROPERTY@got_cr_revision_cp@\"refs/heads/master@{#170242}\"@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]