Update roles/matrix-prometheus-postgres-exporter/tasks/init.yml

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

roles/matrix-prometheus-postgres-exporter/tasks/init.yml

@@ -23,7 +23,7 @@
               resolver 127.0.0.11 valid=5s;
               set $backend "matrix-prometheus-postgres-exporter:9187";
               proxy_pass http://$backend/metrics;
-            {% elif matrix_prometheus_node_exporter_container_http_host_bind_port != '' %}
+            {% elif matrix_prometheus_postgres_exporter_matrix_nginx_proxy_not_enabled_proxy_pass_host != '' %}
               proxy_pass http://{{ matrix_prometheus_postgres_exporter_matrix_nginx_proxy_not_enabled_proxy_pass_host }}/metrics;
             {% else %}
               return 404 "matrix-nginx-proxy is disabled and no host port was bound to the container, so metrics are unavailable";