[Release] Removed not needed revert feature from merge_to_branch.py

[Release] Removed not needed revert feature from merge_to_branch.py

This feature is no longer needed because of the autotag bot.

NOTRY=true
LOG=N
R=machenbach@chromium.org

Committed: https://crrev.com/7ccf444572d55b1cd1be92e4e71726ad3482b89e
Cr-Commit-Position: refs/heads/master@{#31053}

[Michael Hablich, 2015-10-01 13:38:19]

Seems like this was not even covered by UnitTests despite that of line 1160 in
test_scripts.py.

PTAL

[Michael Achenbach, 2015-10-01 14:16:40]

lgtm

[Michael Hablich, 2015-10-01 15:19:16]

The CQ bit was checked by hablich@chromium.org

[commit-bot: I haz the power, 2015-10-01 15:19:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1384523002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1384523002/1

[commit-bot: I haz the power, 2015-10-01 15:21:22]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-01 15:23:16]

Patchset 1 (id:??) landed as
https://crrev.com/7ccf444572d55b1cd1be92e4e71726ad3482b89e
Cr-Commit-Position: refs/heads/master@{#31053}