e2e: add ClientTLSCertAuth coverage for curl v3 auth tests
e2e: add ClientTLSCertAuth coverage for curl v3 auth tests

Signed-off-by: Sam Batschelet <eebdbe215779e06aa0285d26936ee9141aa3d260@redhat.com>

rnaveiras/etcd,gyuho/etcd,ajityagaty/etcd,rnaveiras/etcd,mkumatag/etcd,li-ang/etcd,coreos/etcd,coreos/etcd,li-ang/etcd,etcd-io/etcd,cockroachdb/etcd,etcd-io/etcd,mqliang/etcd,ajityagaty/etcd,joshix/etcd,dannysauer/etcd,rnaveiras/etcd,mqliang/etcd,cockroachdb/etcd,mqliang/etcd,joshix/etcd,etcd-io/etcd,ajityagaty/etcd,dannysauer/etcd,mkumatag/etcd,mkumatag/etcd,gyuho/etcd