NSX-v lbaas requires lbaas's network attached to an exclusive router.
To run lbaas tests on upstream implemantion, we need to remove
rotuer_type attributes at creating router.
Fixed lbaas API:
delete-all load-balanacer resources without deleting listeners.
wait for status function is now at load_balancers client.
Lbaas scenario tests replace urllib2 with urllib3.
Change-Id: Ief935eff8007c4c46115309f55ab3447ce146340