Nova Docker: Metadata service doesn't work

The metadata services rejects the request because the remote IP address
belongs to the docker network. The remote IP address is correct by using
the nova network as default route.

Change-Id: I410a9bfea560f669515b31db7f007515b4d5c4e7
Closes-Bug: #1259267
Closes-Bug: #1261021
Merge "Nova Docker: Metadata service doesn't work"