cit.py: Use infra.git's cit branch instead of the deployed branch

So that we can roll the cit.py pin without breaking other services.

BUG=

Change-Id: I5992d753d8ddf23c29f1ef6c09866a86c7f7c2ae
Reviewed-on: https://chromium-review.googlesource.com/450760Reviewed-by: Daniel Jacques <dnj@chromium.org>
Commit-Queue: Ryan Tseng <hinoka@chromium.org>

cit.py

@@ -146,7 +146,7 @@ def run(args):
 
 def main():
   parser = argparse.ArgumentParser("Chrome Infrastructure CLI.")
-  parser.add_argument('-b', '--infra-branch', default='deployed',
+  parser.add_argument('-b', '--infra-branch', default='cit',
       help="The name of the 'infra' branch to use (default is %(default)s).")
   parser.add_argument('args', nargs=argparse.REMAINDER)