Fix a few more instanes of frontend env variables.

admin/src/client/System/System.js

@@ -33,11 +33,6 @@ function planName(planType) {
   }
 }
 
-var backend_server =
-  process.env["BACKEND_SERVER"] != null
-    ? process.env["BACKEND_SERVER"]
-    : "https://api.openmhz.com";
-
 class System extends Component {
   constructor(props) {
     super(props);

frontend/src/client/Main/Main.js

@@ -53,8 +53,6 @@ const HomepageHeading = ({ mobile }) => (
   </Container>
 )
 
-var site_name = process.env['SITE_NAME'] != null ? process.env['SITE_NAME'] : "OpenMHz";
-
 /*
 HomepageHeading.propTypes = {
   mobile: PropTypes.bool,

frontend/src/server/index.js

@@ -71,6 +71,7 @@ app.get("*", (req, res, next) => {
 			const freePlanValue = ${freePlanValue};
 			const proPlanArchive = ${proPlanArchive};
 			const freePlanArchive = ${freePlanArchive};
+			const site_name = "${site_name}";
 		</script>
 		<script src="${backend_server}/socket.io/socket.io.js"></script>
 		<script>
@@ -100,4 +101,4 @@ app.listen(app.get("port"), app.get("host"), (err) => {
 	} else {
 		console.log(`App listening on port ${app.get("port")} [${process.env.NODE_ENV} mode]`)
 	}
-})
+})