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