Use with for file IO.
Use with for file IO.

Use with for file IO, instead of keeping track of state myself.

Change-Id: Ifc1a49fa51d3e7da08da32fb0966f2637089b58a

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