lxd/network/driver/bridge: Don't refresh BGP prefixes during forward update
lxd/network/driver/bridge: Don't refresh BGP prefixes during forward update

As forward listen address cannot be changed during update.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

stgraber/lxd,lxc/lxd,lxc/lxd,stgraber/lxd,stgraber/lxd,hallyn/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd