xfs_repair: initialize non-leaf finobt blocks with correct magic

xfs_repair: initialize non-leaf finobt blocks with correct magic

The free inode btree construction code in xfs_repair has a bug where
any non-leaf nodes outside of the leftmost block at the associated
level in the tree are incorrectly initialized with the inobt magic
value. Update the prop_ino_cursor() path responsible for growing the
non-leaf portion of the inode btrees to use the btnum of the
specific tree being generated rather than the hardcoded inode btree
type.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reported-by: Lucas Stach <l.stach@pengutronix.de>
Root-caused-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>