Override BAGPIPE_DIR before sourcing bagpipe-bgp plugin.sh
Override BAGPIPE_DIR before sourcing bagpipe-bgp plugin.sh

Else, BAGPIPE_DIR will not point to the right location.

Change-Id: Ic0f56add417a218fbb8e4b14969f18a472f8d280

openstack/networking-bagpipe,openstack/networking-bagpipe-l2,stackforge/networking-bagpipe-l2,openstack/networking-bagpipe,stackforge/networking-bagpipe-l2,openstack/networking-bagpipe-l2