- Add a log entry for repo verb handling and make the container usage calculation take it into account

- Move all the repo push/pull/verb logging into a central track_and_log method
- Readd images accidentally deleted in the last CL
- Make the uncompressed size migration script better handle exceptions

test/data/registry/us/sharedimages/6a787f8c-3cc9-b656-b7b0-988c54878741/diffs.json

@@ -0,0 +1,7 @@
+{
+  "removed": [], 
+  "added": [
+    "/elasticsearch-0.90.5.tar.gz"
+  ], 
+  "changed": []
+}