Add Neutron support

Currently create instance doesnt work in OS installation with Neutron.
To get it work, additional parameter 'nics' should be specified
in Nova 'create' call.
This change allows user to pass 'nics' parameter when create instance.
Also possible to specify list of network IDs which should be attached
to instance if networks are not specified by user.

Closes-Bug: #1257838

Change-Id: Ifd98a880dfa22e9677e802bcd779acd9146ec671
Merge "Add Neutron support"