Fix for OPENSTACK-1119, OPENSTACK-1120
Fix for OPENSTACK-1119, OPENSTACK-1120

Added a bunch of input parameter validations.

Change-Id: I8a6c711c22fd1a0c0a303da45c0202769a5a48ee
Closes-Bug: OPENSTACK-1119, OPENSTACK-1120

naveensan1/nuage-openstack-neutron,nuagenetworks/nuage-openstack-neutron,naveensan1/nuage-openstack-neutron,nuagenetworks/nuage-openstack-neutron