Fix account quota mw for handling a bad source path

The copy source must be container/object.
This patch avoids the server to return
an internal server error when user provides
a path without a container.

Change-Id: I8ea4e62b2a00c4b4a1666d30411a6c93a4f848a5
Fixes: bug #1254626
Merge "Fix account quota mw for handling a bad source path"