Autotest upstream merge.

Merged from d9d64b855363d214996b187380532d4cc9991d29 to
7bad38846fe9c74e42018131ce85aec2b5e6c7a9

BUG=none
TEST=emerge autotest, run bvt, smoke.

Change-Id: Ibe6462198e84e0d41fa160af086283cd712da4a6
Reviewed-on: http://gerrit.chromium.org/gerrit/7440
Tested-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
diff --git a/mirror/source.py b/mirror/source.py
index ec60250..4c6e51c 100644
--- a/mirror/source.py
+++ b/mirror/source.py
@@ -24,7 +24,7 @@
 
 
     def get_new_files(self):
-        raise NotImplemented('get_new_files not implemented')
+        raise NotImplementedError('get_new_files not implemented')
 
 
     def store_files(self, files):