in-band: Do not use manager with loopback address for in-band control.

in-band: Do not use manager with loopback address for in-band control.

If the manager resides on the same host as ovs, the manager target will
be the loopback address.  Then, if in-band is enabled on a bridge, the
in-band module will constantly checks the connection to the manager to
make sure the manager is reachable.  However, the connection checking
implementation cannot identify the route for the loopback address and
will keep issuing the following warning:

|in_band|WARN|cannot find route for controller (127.0.0.1): No such
device or address.

To fix this, this commit makes ovs not consider manager with loopback
for in-band control at all, since the manager is always reachable
on the same host.

Signed-off-by: Alex Wang <alexw@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>