Add short options for git cl presubmit

Adding -u and -f as short options for --upload and --force.
There is precedent for these short options elsewhere in
git_cl.py

TBR=maruel@chromium.org

Review URL: https://chromiumcodereview.appspot.com/11783007

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@175310 0039d316-1c4b-4281-b951-d872f2087c98

git_cl.py

@@ -1053,9 +1053,9 @@ def CreateDescriptionFromLog(args):
 
 def CMDpresubmit(parser, args):
   """run presubmit tests on the current changelist"""
-  parser.add_option('--upload', action='store_true',
+  parser.add_option('-u', '--upload', action='store_true',
                     help='Run upload hook instead of the push/dcommit hook')
-  parser.add_option('--force', action='store_true',
+  parser.add_option('-f', '--force', action='store_true',
                     help='Run checks even if tree is dirty')
   (options, args) = parser.parse_args(args)