iotests: Remove superfluous rm from 232

This test creates no such file.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 20190210145736.1486-4-mreitz@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

tests/qemu-iotests/232

@@ -29,7 +29,6 @@ status=1	# failure is the default!
 _cleanup()
 {
     _cleanup_test_img
-    rm -f $TEST_IMG.snap
 }
 trap "_cleanup; exit \$status" 0 1 2 3 15