[XFS] Fixed an assertion failure in xfs_reclaim caused by delayed block.

The assertion failure came from XFS QA41. The fix is done by enabling
truncate for delayed block in xfs_inactive.

SGI-PV: 945412
SGI-Modid: xfs-linux-melb:xfs-kern:202521a

Signed-off-by: Yingping Lu <yingping@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>