webob exception incorrectly used in v1 images.py
webob exception incorrectly used in v1 images.py

Fixes bug 1010681

Change-Id: I42cf5a8e87e07b94fbba4af7ad3b16a62817007e

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