[XFS] Catch errors resetting quota flags.

Warn to the syslog if we fail to reset the quota flags in the superblock
when a quota check fails.

SGI-PV: 980084
SGI-Modid: xfs-linux-melb:xfs-kern:30789a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>