If we ever screw up the quota reservations enough to trip the
assertions, something's wrong with the quota code.  Shut down the
filesystem when this happens, because this is corruption.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>