Adding router HA to N1kv plugin.

Change-Id: I939d6e8a554c491344d9b0d008a4a3f6eccf3827
Ensure ha:enabled attribute is always added when router is created.

Change-Id: Ic5d3d315b02d15bc392fca7957c0909ec823f9ab
Use CSR1kv as default router type.

Change-Id: I3709c5395b70afd3a617fd87a95b767559304205
Improve ensuring that ha:enabled attribute is always reported.

Change-Id: I9f99e1615ee69b922dc5144a9cd6b5c9c8f23fda
More fixes of last silly bug.

Change-Id: I0e380693ab6cdcb9df87068ff97dfd6bd56b105b