Adds support for the Indigo Virtual Switch (IVS)

Implements: blueprint ivs-vif-driver

Adds line to rootwrap config to allow call to ivs-ctl to control the Indigo switch.
Adds a new 'ivs' VIF type in network/model.py.
Adds support to the LibvirtGenericVIFDriver class for the IVS switch.
Adds functions to linux_net.py to create and delete IVS vif ports.
Adds unit tests to test the new IVS methods.

Change-Id: I65436b82f65374103644af8aba9dba14ba73f94c
Accept is_public=None when listing all flavors

nova-client uses a None (with capital N) when listing all the flavors.
Right now this is interpreted as a wrong query by n-api preventing us
from listing the private flavors using the nova-client.

Fixes bug #1190239

Change-Id: I2a9b1c24cd744c8819c1d41e0ad103d05398401c
Merge "Adds support for the Indigo Virtual Switch (IVS)"
Merge "Accept is_public=None when listing all flavors"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp