Enable uploading a development hash to google3.

This CL also avoids unneeded login prompts.

Change-Id: I6c9c719bba42b88910c41e8d1d214d714a24d5f8
diff --git a/tools/utils.py b/tools/utils.py
index 5d574ac..314fcd2 100644
--- a/tools/utils.py
+++ b/tools/utils.py
@@ -395,7 +395,9 @@
     tar.extractall(path=dirname)
 
 def check_gcert():
-  subprocess.check_call(['gcert'])
+  status = subprocess.call(['gcertstatus'])
+  if status != 0:
+    subprocess.check_call(['gcert'])
 
 # Note that gcs is eventually consistent with regards to list operations.
 # This is not a problem in our case, but don't ever use this method