rename ExtensionsResource to ExtensionsController
rename ExtensionsResource to ExtensionsController

every other "resource" in the api is named either *Controller or just
Controller, so updating this one to match, no effect on anything.

here's a little audit of just about all the nova api calls, the stuff at
the bottom shows some stats:
https://gist.githubusercontent.com/termie/9500927/raw/ac724f0762224bc60bb79c4b0fecfdd12afe5ca7/calls

Change-Id: I71df08048d5b0fa868f68bfe9cb9176507dde3b7

sebrandon1/nova,tangfeixiong/nova,takeshineshiro/nova,eonpatapon/nova,bgxavier/nova,Stavitsky/nova,orbitfp7/nova,blueboxgroup/nova,dims/nova,varunarya10/nova_test_latest,yatinkumbhare/openstack-nova,belmiromoreira/nova,klmitch/nova,openstack/nova,rahulunair/nova,eonpatapon/nova,felixma/nova,mahak/nova,Juniper/nova,ruslanloman/nova,JioCloud/nova_test_latest,petrutlucian94/nova,rajalokan/nova,JioCloud/nova_test_latest,gooddata/openstack-nova,rajalokan/nova,dawnpower/nova,mgagne/nova,mandeepdhami/nova,tealover/nova,eayunstack/nova,TwinkleChawla/nova,raildo/nova,silenceli/nova,CEG-FYP-OpenStack/scheduler,Tehsmash/nova,vladikr/nova_drafts,LoHChina/nova,yosshy/nova,hanlind/nova,hanlind/nova,leilihh/novaha,mikalstill/nova,badock/nova,gooddata/openstack-nova,openstack/nova,bigswitch/nova,cloudbase/nova-virtualbox,takeshineshiro/nova,maelnor/nova,iuliat/nova,nikesh-mahalka/nova,vmturbo/nova,mikalstill/nova,leilihh/nova,orbitfp7/nova,devendermishrajio/nova,luogangyi/bcec-nova,ted-gould/nova,felixma/nova,akash1808/nova_test_latest,cloudbase/nova,devendermishrajio/nova_test_latest,redhat-openstack/nova,blueboxgroup/nova,watonyweng/nova,MountainWei/nova,berrange/nova,tealover/nova,isyippee/nova,petrutlucian94/nova,edulramirez/nova,jianghuaw/nova,LoHChina/nova,virtualopensystems/nova,affo/nova,silenceli/nova,akash1808/nova,shahar-stratoscale/nova,saleemjaveds/https-github.com-openstack-nova,klmitch/nova,leilihh/nova,varunarya10/nova_test_latest,spring-week-topos/nova-week,badock/nova,raildo/nova,adelina-t/nova,BeyondTheClouds/nova,j-carpentier/nova,vmturbo/nova,whitepages/nova,barnsnake351/nova,akash1808/nova,isyippee/nova,cernops/nova,fnordahl/nova,CloudServer/nova,edulramirez/nova,JianyuWang/nova,luogangyi/bcec-nova,yosshy/nova,mikalstill/nova,gooddata/openstack-nova,belmiromoreira/nova,klmitch/nova,cernops/nova,vmturbo/nova,rahulunair/nova,zaina/nova,zzicewind/nova,zzicewind/nova,phenoxim/nova,dims/nova,joker946/nova,vladikr/nova_drafts,BeyondTheClouds/nova,eayunstack/nova,viggates/nova,scripnichenko/nova,tanglei528/nova,Metaswitch/calico-nova,vmturbo/nova,mahak/nova,Juniper/nova,CCI-MOC/nova,cloudbase/nova-virtualbox,alexandrucoman/vbox-nova-driver,mahak/nova,Francis-Liu/animated-broccoli,virtualopensystems/nova,thomasem/nova,jianghuaw/nova,shail2810/nova,eharney/nova,mgagne/nova,iuliat/nova,Juniper/nova,tangfeixiong/nova,noironetworks/nova,rajalokan/nova,zhimin711/nova,bigswitch/nova,alaski/nova,MountainWei/nova,sebrandon1/nova,adelina-t/nova,shail2810/nova,sebrandon1/nova,viggates/nova,yatinkumbhare/openstack-nova,double12gzh/nova,alexandrucoman/vbox-nova-driver,NeCTAR-RC/nova,nikesh-mahalka/nova,whitepages/nova,jianghuaw/nova,JioCloud/nova,tanglei528/nova,alaski/nova,eharney/nova,dawnpower/nova,watonyweng/nova,TwinkleChawla/nova,cyx1231st/nova,cloudbase/nova,kimjaejoong/nova,alvarolopez/nova,gooddata/openstack-nova,CiscoSystems/nova,bgxavier/nova,saleemjaveds/https-github.com-openstack-nova,hanlind/nova,jeffrey4l/nova,cloudbase/nova,Francis-Liu/animated-broccoli,angdraug/nova,joker946/nova,Yusuke1987/openstack_template,JianyuWang/nova,shahar-stratoscale/nova,openstack/nova,projectcalico/calico-nova,leilihh/novaha,mandeepdhami/nova,alvarolopez/nova,tianweizhang/nova,apporc/nova,berrange/nova,Tehsmash/nova,devendermishrajio/nova,cyx1231st/nova,barnsnake351/nova,JioCloud/nova,jeffrey4l/nova,noironetworks/nova,Juniper/nova,tudorvio/nova,fnordahl/nova,double12gzh/nova,j-carpentier/nova,CloudServer/nova,ruslanloman/nova,affo/nova,klmitch/nova,CCI-MOC/nova,phenoxim/nova,kimjaejoong/nova,zhimin711/nova,NeCTAR-RC/nova,spring-week-topos/nova-week,BeyondTheClouds/nova,maelnor/nova,ted-gould/nova,mmnelemane/nova,mmnelemane/nova,Metaswitch/calico-nova,scripnichenko/nova,apporc/nova,rajalokan/nova,tianweizhang/nova,redhat-openstack/nova,rahulunair/nova,akash1808/nova_test_latest,CEG-FYP-OpenStack/scheduler,tudorvio/nova,Yusuke1987/openstack_template,CiscoSystems/nova,zaina/nova,thomasem/nova,Stavitsky/nova,jianghuaw/nova,devendermishrajio/nova_test_latest,cernops/nova,projectcalico/calico-nova,angdraug/nova