Change path of docker hub login.

entrypoint.sh

@@ -23,7 +23,10 @@ echo_and_run() {
 docker_login() {
     login_name="$1"
     if [ -z "$login_name" ]; then
-        login_name=docker.io
+        login_name="$DEFAULT_DOMAIN"
+    fi
+    if [ "$login_name" = "$DEFAULT_DOMAIN" ]; then
+        login_name="$DEFAULT_DOMAIN/v1"
     fi
     # TODO: detect registry url
     mkdir -p "$HOME/.docker"
@@ -102,7 +105,7 @@ if [ -n "$username" ]; then
         fail "need to also give password when logging in"
     fi
     if [ -z "$repository" ]; then
-        docker_login "$DEFAULT_DOMAIN"
+        docker_login ''
     else
         docker_login "$(split_repo_domain "$repository" | head -n1)"
     fi