Revert "Install simplejson in devstack venv"

This reverts commit 6990b06. This
should no longer be necessary as packages are requiring simplejson.

Change-Id: I74b0f93457f91e7d53d54737d52f67075088faca
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

Author: stephenfin

inc/python

@@ -42,9 +42,6 @@ function setup_devstack_virtualenv {
         # available on pypi.
         $PYTHON -m venv --system-site-packages "${DEVSTACK_VENV}"
         pip_install -U pip setuptools[core]
-        #NOTE(rpittau): workaround for simplejson removal in osc
-        #  https://review.opendev.org/c/openstack/python-openstackclient/+/920001
-        pip_install -U simplejson
     fi
     if [[ ":$PATH:" != *":$DEVSTACK_VENV/bin:"* ]] ; then
         export PATH="$DEVSTACK_VENV/bin:$PATH"