Make the auto-pusher recover easier.

Make the auto-pusher recover easier.

The auto-push script is only used in an automated fashion
on bots. It doesn't need to check for a clean git
environment as it has a special workdir checkout.

If the release creation fails for whatever reason (e.g.
a master restart happens in the middle), the workdir
checkout might be left dirty. Any new attempt of the auto
pusher then bails out.

After this change it will call the create_release script
in any case which tidies up the workspace on startup.

TBR=tandrii@chromium.org
NOTRY=true
TEST=./script_test.py

Committed: https://crrev.com/002b1ddb0e1aa5172b644f9d9b29caa05e830650
Cr-Commit-Position: refs/heads/master@{#26928}

[Michael Achenbach, 2015-02-27 15:09:31]

machenbach@chromium.org changed reviewers:
+ hablich@chromium.org, tandrii@chromium.org

[Michael Achenbach, 2015-02-27 15:13:31]

PTAL

[tandrii(chromium), 2015-02-27 16:32:47]

lgtm

[Michael Achenbach, 2015-02-27 22:22:27]

The CQ bit was checked by machenbach@chromium.org

[commit-bot: I haz the power, 2015-02-27 22:23:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/960773007/1

[commit-bot: I haz the power, 2015-02-27 22:23:31]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-27 22:23:46]

Patchset 1 (id:??) landed as
https://crrev.com/002b1ddb0e1aa5172b644f9d9b29caa05e830650
Cr-Commit-Position: refs/heads/master@{#26928}