Add and update subnet properties in Cisco N1kv plugin

Add dns nameservers and dhcp info in subnet create.
Update subnet properties.

Change-Id: I70e3f0261f6ba5433bbf08d33e2a34cdbb20fed2
Closes-Bug: #1276876
Merge "Add and update subnet properties in Cisco N1kv plugin"
Imported Translations from Transifex

Change-Id: Iafb65bdd55952a9f8dba3f48c53c691f07ef344c