Use code-block for curl examples
Use code-block for curl examples

The code-block directive wasn't used for literal blocks in the
curl examples document, so they weren't highlighted nicely.

Change-Id: If0165ec666003682695c06a9b4ae840016b8355b

rodrigods/keystone,vivekdhayaal/keystone,jumpstarter-io/keystone,rushiagr/keystone,dstanek/keystone,dstanek/keystone,ilay09/keystone,nuxeh/keystone,rushiagr/keystone,vivekdhayaal/keystone,UTSA-ICS/keystone-kerberos,jumpstarter-io/keystone,ajayaa/keystone,openstack/keystone,MaheshIBM/keystone,rajalokan/keystone,reeshupatel/demo,jonnary/keystone,openstack/keystone,cernops/keystone,ajayaa/keystone,idjaw/keystone,takeshineshiro/keystone,ilay09/keystone,rajalokan/keystone,klmitch/keystone,klmitch/keystone,reeshupatel/demo,nuxeh/keystone,roopali8/keystone,openstack/keystone,dims/keystone,roopali8/keystone,ging/keystone,rodrigods/keystone,rushiagr/keystone,mahak/keystone,himanshu-setia/keystone,dims/keystone,vivekdhayaal/keystone,promptworks/keystone,mahak/keystone,maestro-hybrid-cloud/keystone,nuxeh/keystone,jumpstarter-io/keystone,jonnary/keystone,mahak/keystone,reeshupatel/demo,promptworks/keystone,rajalokan/keystone,jamielennox/keystone,ilay09/keystone,takeshineshiro/keystone,cernops/keystone,dstanek/keystone,himanshu-setia/keystone,promptworks/keystone,jamielennox/keystone,MaheshIBM/keystone,blueboxgroup/keystone,blueboxgroup/keystone,maestro-hybrid-cloud/keystone,idjaw/keystone,UTSA-ICS/keystone-kerberos,ging/keystone