common/rc: fix unknown _xfs_repair_test_fs function name

common/rc: fix unknown _xfs_repair_test_fs function name

Sometimes I hit below errors:
  ./common/rc: line 1293: _xfs_repair_test_fs: command not found
  ./common/rc: line 1298: _xfs_repair_test_fs: command not found

The _repair_test_fs trys to call _xfs_repair_test_fs(), but there's
not that function in fstests. According to commit c7d81cdecbef,
it brought in _test_xfs_repair, but called wrong name. So fix it.

Fixes: c7d81cdecbef ("check: try to fix the test device if it gets corrupted")
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>