- use xfs_repair instead of extinct xfs_check (bsc#899930)

No testsuite; requires integration tests. With mocking it's not possible to detect vanishing programs.
yes, check program is fine for me. But calling repair problem looks strange, so I think some easy explanation like `use xfs_repair instead of extinct xfs_check (bsc#899930)` so it is obvious why check is not used like in other cases