tests: don't leave cruft behind on the TEST_MNT

Don't leave cruft behind on the test device's filesystem, so as to
avoid filling it with debris.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

tests/generic/111

@@ -37,7 +37,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 _cleanup()
 {
     cd /
-    rm -f $tmp.*
+    rm -f $tmp.* "$TESTDIR"
 }
 
 # get standard environment, filters and checks