Use unique per-test S3 bucket name.
Use unique per-test S3 bucket name.

Addresses bug 955527

Avoids a race between the S3 testcase body and the bucket clean-out
in the S3 test teardown, running near concurrently in the Jenkins
python26 and python27 builds.

Change-Id: I10f013b02bb74db2cbfc692ed372121d21bca3fb

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