Nicira plugin: always fetch lports from correct lswitch

Bug 1188652

Remove get_logical_port_status which required a lswitch uuid, and
replace it with a call to query_lswitch_ports, which does not
require it.

Change-Id: I6c7d0403f37b2c9fb4332a8d34dcaa9050ced3fc
Merge branch 'stable/grizzly' of https://github.com/openstack/quantum into grizzly/stable