Update README to reflect LBaaS postman collection.
Update README to reflect LBaaS postman collection.

Change-Id: I53057cd71fed174debbf1e6be579fb36e3d76b41
Signed-off-by: Alexis de Talhouët <3f85d13b1d0fb141169e8f22f55d7ee87dcd5f00@inocybe.com>

opendaylight/netvirt,opendaylight/netvirt,opendaylight/netvirt,opendaylight/netvirt,opendaylight/netvirt