fix e2e test argument

Author: asungur

hack/run-e2e.sh

@@ -28,7 +28,7 @@ cd $ROOT
 PROVIDER=${PROVIDER:-}
 if [ "$PROVIDER" == "gke" ]; then
     KUBERNETES_SRC=
-    KUBERNETES_PROVIDER=gke
+    KUBERNETES_PROVIDER=gce
     KUBERNETES_CONFORMANCE_PROVIDER=gke
     KUBE_GCE_ZONE=${GCP_ZONE:-}
     PROJECT=${GCP_PROJECT:-}