mtd: ubi: don't leak e if schedule_erase() fails

If __erase_worker() fails to erase the EB and schedule_erase() fails as
well to do anything about it then we go RO. But that is not a reason to
leak the e argument here. Therefore clean up e.

CRs-Fixed: 975289
Change-Id: Iec8f4777d91ae36a6196807d7d42bc072f70b41f
Cc: <stable@vger.kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Git-commit: 6b238de189f69dc77d660d4cce62eed15547f4c3
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>