Quantumapi returns an empty network list

When nova retries network list and if the list is empty, quantumapi
should return a empty list instead of an empty dictionnary.

Fixes bug 1189976

Change-Id: I5b8c498a6c86e92d0de14d8de9e55722408c5669
Merge "Quantumapi returns an empty network list"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp