btrfs: fix raid56 scrub failed in xfstests btrfs/072
btrfs: fix raid56 scrub failed in xfstests btrfs/072

The xfstests btrfs/072 reports uncorrectable read errors in dmesg,
because scrub forgets to use commit_root for parity scrub routine
and scrub attempts to scrub those extents items whose contents are
not fully on disk.

To fix it, we just add the @search_commit_root flag back.

Signed-off-by: Gui Hecheng <1c5d69841cd43aa5bd620389a9dfe310c76cb958@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <f41a7033a6382ce00d6b717e37d942dbe3c9a107@cn.fujitsu.com>
Reviewed-by: Miao Xie <f936f6dff2e42e099f2690978a0c285fbb9344ae@huawei.com>
Signed-off-by: Chris Mason <e2e8c5702d8ed5f565988a1cf5bb35c9ce199e5e@fb.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs