xfs: Hoist node transaction handling

xfs: Hoist node transaction handling

Source kernel commit: 3f562d092bb1edd39bfc0e6808d7108d47f8aa3a

This patch basically hoists the node transaction handling around the
leaf code we just hoisted.  This will helps setup this area for the
state machine since the goto is easily replaced with a state since it
ends with a transaction roll.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>