[TrivialFix]Remove duplicated OS::Nova::Flavor registration
[TrivialFix]Remove duplicated OS::Nova::Flavor registration

Change-Id: I19b3c87fa855aca33ca57f185c615f8672992740

yeming233/horizon,sandvine/horizon,noironetworks/horizon,bac/horizon,NeCTAR-RC/horizon,NeCTAR-RC/horizon,BiznetGIO/horizon,openstack/horizon,noironetworks/horizon,wolverineav/horizon,ChameleonCloud/horizon,openstack/horizon,sandvine/horizon,NeCTAR-RC/horizon,ChameleonCloud/horizon,bac/horizon,wolverineav/horizon,ChameleonCloud/horizon,noironetworks/horizon,BiznetGIO/horizon,bac/horizon,noironetworks/horizon,bigswitch/horizon,BiznetGIO/horizon,yeming233/horizon,openstack/horizon,wolverineav/horizon,sandvine/horizon,coreycb/horizon,NeCTAR-RC/horizon,sandvine/horizon,wolverineav/horizon,openstack/horizon,bigswitch/horizon,ChameleonCloud/horizon,coreycb/horizon,bigswitch/horizon,coreycb/horizon,bac/horizon,yeming233/horizon,yeming233/horizon,BiznetGIO/horizon,bigswitch/horizon,coreycb/horizon