This commit contains two fixes:
1. ``of_listen_address``: We use the xenapi's facts directly, so
that we can avoid depending on facts gathered by setup for hosts;
This is useful when deploy on the role of neutron only (--tag neutron);
2. ``local_ip``: Get the proper IP for tunnel. It should be chosen
from dom0's IP which is in the same network where tunnel interface
is connected.
blueprint: xenserver-support
Change-Id: I61bbd6499323e3fddd6293a0df6baec34dbddf23
c8245edf91