xfs: remove redundant assignment to variable error

Variable error is being initialized with a value that is never read
and is being re-assigned a couple of statements later on. The
assignment is redundant and hence can be removed.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>