Fix 'glance-cache-manage -h' default interpolation
Fix 'glance-cache-manage -h' default interpolation

Some options were showing up as %(default)s when running
"glance-cache-manage -h".

Fixes bug 1197472

Change-Id: I1c7586cbc52445e3bdca28a71378f40ecb5b07a9

darren-wang/gl,cloudbau/glance,openstack/glance,rajalokan/glance,vuntz/glance,scripnichenko/glance,scripnichenko/glance,dims/glance,dims/glance,jumpstarter-io/glance,sigmavirus24/glance,kfwang/Glance-OVA-OVF,tanglei528/glance,citrix-openstack-build/glance,takeshineshiro/glance,SUSE-Cloud/glance,akash1808/glance,wkoathp/glance,sigmavirus24/glance,redhat-openstack/glance,takeshineshiro/glance,ntt-sic/glance,tanglei528/glance,openstack/glance,SUSE-Cloud/glance,cloudbau/glance,paramite/glance,JioCloud/glance,kfwang/Glance-OVA-OVF,wkoathp/glance,ozamiatin/glance,ntt-sic/glance,akash1808/glance,ozamiatin/glance,vuntz/glance,JioCloud/glance,redhat-openstack/glance,stevelle/glance,openstack/glance,rajalokan/glance,rickerc/glance_audit,darren-wang/gl,jumpstarter-io/glance,citrix-openstack-build/glance,stevelle/glance,klmitch/glance,paramite/glance,saeki-masaki/glance,saeki-masaki/glance,klmitch/glance,rickerc/glance_audit