add scheduled_delete_from_backend which delays the deletion of images for at least 1 second
add scheduled_delete_from_backend which delays the deletion of images for at least 1 second

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