xfs: fix uninitialized variable in xfs_scrub_quota

On the first pass through the while(1) loop, we get to
xfs_scrub_should_terminate() which can test the uninitialized
error variable.

Fixes-coverity-id: 1423737
Fixes: c2fc338c ("xfs: scrub quota information")
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

fs/xfs/scrub/quota.c

@@ -207,7 +207,7 @@ xfs_scrub_quota(
 	xfs_dqid_t			id = 0;
 	uint				dqtype;
 	int				nimaps;
-	int				error;
+	int				error = 0;
 
 	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
 		return -ENOENT;