Corrected instance interface api doc.
Corrected instance interface api doc.

fixed urls and made input params documentation clearer.

Change-Id: Iefe22d3a73391dc70f44c60ab3fb6ff600b604c2

rackerlabs/melange,openstack-attic/melange,rackerlabs/melange,rajarammallya/melange,rackerlabs/melange,openstack-attic/melange,rajarammallya/melange,openstack-attic/melange,rajarammallya/melange