Replace openstack.org git:// URLs with https://

This is a mechanically generated change to replace openstack.org
git:// URLs with https:// equivalents.

This is in aid of a planned future move of the git hosting
infrastructure to a self-hosted instance of gitea (https://gitea.io),
which does not support the git wire protocol at this stage.

This update should result in no functional change.

For more information see the thread at

 http://lists.openstack.org/pipermail/openstack-discuss/2019-March/003825.html

Change-Id: Ib994d00e54ea525b3baf33e1c2f5c41beedb2511

tools/tox_install.sh

@@ -32,7 +32,7 @@ elif [ -x "$ZUUL_CLONER" ]; then
     $ZUUL_CLONER --cache-dir \
         /opt/git \
         --branch $BRANCH_NAME \
-        git://git.openstack.org \
+        https://git.openstack.org \
         openstack/neutron
     cd openstack/neutron
     $install_cmd -e .