xfs: Remove xfs_trans_roll in xfs_attr_node_removename

A transaction roll is not necessary immediately after setting the
INCOMPLETE flag when removing a node xattr entry with remote value
blocks. The remote block invalidation that immediately follows setting
the flag is an in-core only change. The next step after that is to start
unmapping the remote blocks from the attr fork, but the xattr remove
transaction reservation includes reservation for full tree splits of the
dabtree and bmap tree. The remote block unmap code will roll the
transaction as extents are unmapped and freed.

Signed-off-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Dave Chinner <dchinner@redhat.com>