tryserver recipe_module: Add get_tags.

recipe_modules/tryserver/example.expected/with_svn_patch.json

Index: recipe_modules/tryserver/example.expected/with_svn_patch.json
diff --git a/recipe_modules/tryserver/example.expected/with_svn_patch.json b/recipe_modules/tryserver/example.expected/with_svn_patch.json
index 1046c033953d50d0e07d978b5639af5ce4ccd8c0..903f8d613b898cd9adc94a6ece7fa8360a262fb3 100644
--- a/recipe_modules/tryserver/example.expected/with_svn_patch.json
+++ b/recipe_modules/tryserver/example.expected/with_svn_patch.json
@@ -32,40 +32,8 @@
     "stdin": "fake patch.diff content (line 1)\nfake patch.diff content (line 2)\n"
   },
   {
-    "cmd": [
-      "git",
-      "diff",
-      "--cached",
-      "--name-only"
-    ],
-    "cwd": "[SLAVE_BUILD]",
-    "name": "git diff to analyze patch",
-    "stdout": "/path/to/tmp/",
-    "~followup_annotations": [
-      "@@@STEP_LOG_LINE@files@foo.cc@@@",
-      "@@@STEP_LOG_END@files@@@",
-      "@@@SET_BUILD_PROPERTY@failure_type@\"INVALID_TEST_RESULTS\"@@@",
-      "@@@SET_BUILD_PROPERTY@subproject_tag@\"v8\"@@@"
-    ]
-  },
-  {
-    "cmd": [
-      "python",
-      "-u",
-      "import sys; sys.exit(1)"
-    ],
-    "cwd": "[SLAVE_BUILD]",
-    "name": "fail",
-    "~followup_annotations": [
-      "step returned non-zero exit code: 1",
-      "@@@STEP_TEXT@foo@@@",
-      "@@@STEP_FAILURE@@@",
-      "@@@SET_BUILD_PROPERTY@failure_hash@\"c2311ad770732eade3d2f48247abd147e40a70e7\"@@@"
-    ]
-  },
-  {
     "name": "$result",
-    "reason": "Step('fail') failed with return_code 1",
+    "reason": "Cannot get tags from gerrit yet.",
     "status_code": 1
   }
 ]