Complete method Verification of os-hypervisors
Complete method Verification of os-hypervisors

verified the API doc for os-hypervisors,
added policy description as this is admin action by default,
Also, remove some common error code like 500, 503 etc

Part of bp:api-ref-in-rst

Change-Id: Ic81eac06cb238d0940feac41940433f9e3befc29

gooddata/openstack-nova,bigswitch/nova,phenoxim/nova,jianghuaw/nova,hanlind/nova,rajalokan/nova,Juniper/nova,cloudbase/nova,jianghuaw/nova,mikalstill/nova,openstack/nova,Juniper/nova,mahak/nova,vmturbo/nova,sebrandon1/nova,cloudbase/nova,openstack/nova,gooddata/openstack-nova,vmturbo/nova,phenoxim/nova,klmitch/nova,cloudbase/nova,jianghuaw/nova,openstack/nova,rajalokan/nova,klmitch/nova,klmitch/nova,Juniper/nova,mahak/nova,mahak/nova,mikalstill/nova,vmturbo/nova,rahulunair/nova,rahulunair/nova,jianghuaw/nova,hanlind/nova,rajalokan/nova,gooddata/openstack-nova,rahulunair/nova,sebrandon1/nova,hanlind/nova,klmitch/nova,sebrandon1/nova,bigswitch/nova,Juniper/nova,gooddata/openstack-nova,rajalokan/nova,alaski/nova,mikalstill/nova,vmturbo/nova,alaski/nova