When create ovs port in nova, it will first create ovs port using
one commnd and set other parameters using seperated commands, but
this isn't the correct way, because once the ovs port is created,
neutron ove agent will monitor the chagne immediately and deals
with the new added port, however, at this time, the other params
are not set in ovs, this patch is to make creating ovs port and
setting corresponding params in one operation
In this patch, we add new Dom0 plugin functions ovs_create_port()
and wrapper file host_network.py for calling Dom0 plugin
Change-Id: Ic7bab9fd3eeed8be3f1493716178189bcf048da1
Partial-Bug: #1649747
5fb4ce9c3e