Make update_server use **kwargs
Make update_server use **kwargs

As we discussed on
http://lists.openstack.org/pipermail/openstack-dev/2015-July/068864.html
All http POST/PUT methods need to contain **kwargs as their arguments.
This patch makes update_server use **kwargs.

Partially implements blueprint consistent-service-method-names

Change-Id: Iac517acbd80d8140461b3e8853573add1ab4a9eb

Juniper/tempest,LIS/lis-tempest,tonyli71/tempest,xbezdick/tempest,tonyli71/tempest,dkalashnik/tempest,masayukig/tempest,zsoltdudas/lis-tempest,openstack/tempest,dkalashnik/tempest,Tesora/tesora-tempest,rakeshmi/tempest,izadorozhna/tempest,vedujoshi/tempest,sebrandon1/tempest,flyingfish007/tempest,cisco-openstack/tempest,flyingfish007/tempest,zsoltdudas/lis-tempest,vedujoshi/tempest,Juniper/tempest,cisco-openstack/tempest,izadorozhna/tempest,bigswitch/tempest,masayukig/tempest,openstack/tempest,sebrandon1/tempest,rakeshmi/tempest,bigswitch/tempest,Tesora/tesora-tempest,xbezdick/tempest,LIS/lis-tempest