Fix network-api direct database hits in metadata server

The metadata server was using a couple of methods from the network
api that caused direct-to-database accesses. Those are no longer
necessary with the object modeling of network resources. This patch
converts those to use objects and avoid the direct database
traffic.

Change-Id: Iea48f74387afa35af3889eebdfa1af169a52ad1d
Closes-bug: #1306009
Merge "Fix network-api direct database hits in metadata server"