Revert of Skip apply_gerrit rebase when there is a rebase failure (patchset #2...

Revert of Skip apply_gerrit rebase when there is a rebase failure (patchset #2 id:20001 of https://codereview.chromium.org/2328313002/ )

Reason for revert:
The "git rebase --abort" should only happen when there is a failure during rebase not when it succeeds.

Original issue's description:
> Skip apply_gerrit rebase when there is a rebase failure.
>
> Not doing so causes a failure in the 'git checkout $base_rev' step as visible here: https://build.chromium.org/p/client.skia.fyi/builders/Infra-PerCommit-Trybot/builds/4995
> This causes the checkout to remain in the "rebase in progress" state.
>
>
> BUG=chromium:645955
> BUG=skia:5749
>
> Committed: https://chromium.googlesource.com/chromium/tools/depot_tools/+/9736fe8938e67337bb45dccf79ae8699b9625fa6

TBR=agable@chromium.org,andybons@chromium.org,tandrii@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:645955

Review-Url: https://codereview.chromium.org/2331103002

recipe_modules/bot_update/resources/bot_update.py

@@ -604,11 +604,7 @@ def apply_gerrit_ref(gerrit_repo, gerrit_ref, root, gerrit_reset,
       try:
         ok = False
         git('checkout', '-b', temp_branch_name, cwd=root)
-        try:
-          git('rebase', base_rev, cwd=root)
-        finally:
-          # Abort the rebase since there were failures.
-          git('rebase', '--abort', cwd=root)
+        git('rebase', base_rev, cwd=root)
 
         # Get off of the temporary branch since it can't be deleted otherwise.
         cur_rev = git('rev-parse', 'HEAD', cwd=root).strip()