migrate env for NGINX_* to PROXY_*

plugins/nginx-vhosts/install

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
+source "$PLUGIN_AVAILABLE_PATH/config/functions"
 
 case "$DOKKU_DISTRO" in
   debian)
@@ -73,6 +75,8 @@ cp "${PLUGIN_CORE_AVAILABLE_PATH}/nginx-vhosts/templates/500-error.html" "${DOKK
 # patch broken nginx 1.8.0 logrotate
 [[ -f /etc/logrotate.d/nginx ]] && sed -i -e 's/invoke-rc.d/service/g' /etc/logrotate.d/nginx
 
+migrate_nginx_to_proxy
+
 case "$DOKKU_DISTRO" in
   debian)
     NGINX_INIT="/usr/sbin/invoke-rc.d"