qemu.tests: Correct file_transfer import link.

We have move file_transfer to generic/tests/
Signed-off-by: NFeng Yang <fyang@redhat.com>

qemu/tests/live_snapshot.py

@@ -2,7 +2,7 @@ import time
 import logging
 from autotest.client.shared import error
 from virttest import utils_test
-from tests import file_transfer
+from generic.tests import file_transfer
 
 
 def run(test, params, env):