Use right function to create extension list for agent test
Use right function to create extension list for agent test

Update the function to create_extension_list after agent merge, also remove
unnecessary hack of extention creation for code clean

Change-Id: I585a62a9070640be241d173e86f2ad9a87bd35b4

sileht/aodh,cernops/ceilometer,eayunstack/ceilometer,eayunstack/ceilometer,fabian4/ceilometer,ityaptin/ceilometer,maestro-hybrid-cloud/ceilometer,pkilambi/ceilometer,redhat-openstack/ceilometer,idegtiarov/ceilometer,cernops/ceilometer,openstack/aodh,openstack/ceilometer,r-mibu/ceilometer,pczerkas/aodh,mathslinux/ceilometer,mathslinux/ceilometer,redhat-openstack/ceilometer,isyippee/ceilometer,ityaptin/ceilometer,chungg/aodh,idegtiarov/ceilometer,Juniper/ceilometer,maestro-hybrid-cloud/ceilometer,pczerkas/aodh,pkilambi/ceilometer,isyippee/ceilometer,Juniper/ceilometer,openstack/aodh,fabian4/ceilometer,sileht/aodh,chungg/aodh,openstack/ceilometer,r-mibu/ceilometer