Add TaaS panel to Horizon dashboard

This will enable the TaaS GUI to the horizon dashbboard.
TaaS dashboard will need to be installed as part of the image,
else it will not try to add the panel.

Change-Id: I226d9d6e46f5b556a7baa88fcd06de8e571bcdff

horizon/templates/bin/_horizon.sh.tpl

@@ -46,6 +46,12 @@ function start () {
   /tmp/manage.py compress --force
   rm -rf /tmp/_tmp_.secret_key_store.lock /tmp/.secret_key_store
 
+  # Add TaaS dashboard panel if available
+  TAAS_PANEL="${SITE_PACKAGES_ROOT}/neutron_taas_dashboard/enabled/_90_project_tapservices_panel.py"
+  if [ -f ${TAAS_PANEL} ]; then
+     ln -s ${TAAS_PANEL}   ${SITE_PACKAGES_ROOT}/openstack_dashboard/local/enabled/_90_project_tapservices_panel.py
+  fi
+
   exec apache2 -DFOREGROUND
 }