Revert "blacklist l10n-bot"

This broke the gate-and-submit pipeline, no CR+2 were being processed
anymore and nothing was being merged.

This reverts commit 93edb45ff90e3f43006b386edf1676369287f5b3.

Change-Id: Ic8cf602a0aa72052c0517edbe38ff5e86f7d235b