Enable --git-cache-dir option in chromite/cbuildbot.

scripts/slave/recipes/cros/cbuildbot_tryjob.expected/release.json

Index: scripts/slave/recipes/cros/cbuildbot_tryjob.expected/release.json
diff --git a/scripts/slave/recipes/cros/cbuildbot_tryjob.expected/external.json b/scripts/slave/recipes/cros/cbuildbot_tryjob.expected/release.json
similarity index 89%
copy from scripts/slave/recipes/cros/cbuildbot_tryjob.expected/external.json
copy to scripts/slave/recipes/cros/cbuildbot_tryjob.expected/release.json
index 5e2504573a93c441d61ff74f06b1f8fa1ba4c723..d3296fc12e18738d980151c3313041ff61d7fba3 100644
--- a/scripts/slave/recipes/cros/cbuildbot_tryjob.expected/external.json
+++ b/scripts/slave/recipes/cros/cbuildbot_tryjob.expected/release.json
@@ -15,7 +15,7 @@
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
-      "chromite@master:",
+      "chromite@release-R55-9999.B:",
       "--output_manifest"
     ],
     "env": {
@@ -27,7 +27,7 @@
       "@@@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@    \"chromite\": \"master:\"@@@",
+      "@@@STEP_LOG_LINE@json.output@    \"chromite\": \"release-R55-9999.B:\"@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"manifest\": {}, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"patch_failure\": false, @@@",
@@ -43,10 +43,10 @@
     "cmd": [
       "git",
       "checkout",
-      "master"
+      "release-R55-9999.B"
     ],
     "cwd": "[SLAVE_BUILD]/chromite",
-    "name": "checkout chromite branch [master]"
+    "name": "checkout chromite branch [release-R55-9999.B]"
   },
   {
     "cmd": [
@@ -54,7 +54,7 @@
       "pull"
     ],
     "cwd": "[SLAVE_BUILD]/chromite",
-    "name": "sync chromite branch [master]"
+    "name": "sync chromite branch [release-R55-9999.B]"
   },
   {
     "cmd": [
@@ -81,6 +81,8 @@
       "[SLAVE_BUILD]/chromite/bin/cbuildbot",
       "--buildroot",
       "[ROOT]/cbuild/external_master",
+      "--git-cache-dir",
+      "/b/cros_git_cache",
       "--timeout",
       "14400",
       "--remote-trybot",