Fix --force implementation to not prompt but still run hooks

Fix --force implementation to not prompt but still run hooks

I found out that some devs thought that -f just skipped the prompt, but it did
in fact also skip the presubmit checks.
Make -f do what it should, no prompt and just return if the presubmit check
failed.

R=cmp@chromium.org
BUG=
TEST=


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=117918

[cmp, 2012-01-17 18:01:36]

lgtm

[commit-bot: I haz the power, 2012-01-17 18:03:54]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/maruel@chromium.org/9240009/1

[commit-bot: I haz the power, 2012-01-17 18:10:18]

Change committed as 117918