Revert virtualenv workaround

It should no longer be necessary.

Ussuri only.

Change-Id: I7f85f17e7b9a8a6d7bc656abbc39ba3dd2deda3a

docker/kolla-toolbox/Dockerfile.j2

@@ -59,7 +59,7 @@ LABEL maintainer="{{ maintainer }}" name="{{ image_name }}" build-date="{{ build
 
 RUN mkdir -p /requirements \
     && curl -sSL -o /requirements/upper-constraints.txt https://releases.openstack.org/constraints/upper/{{ openstack_release }} \
-    && {{ macros.install_pip(kolla_toolbox_pip_virtualenv_packages | customizable("pip_virtualenv_packages"), constraints=false) }} \
+    && {{ macros.install_pip(kolla_toolbox_pip_virtualenv_packages | customizable("pip_virtualenv_packages")) }} \
     && virtualenv --system-site-packages {{ virtualenv_path }}
 
 ENV PATH {{ virtualenv_path }}/bin:$PATH