[gnome-shell] fileUtils: Remove some compatibility code

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit a5a6c699c35e33fe841742952202fde33d942a07
Author: Florian Müllner <fmuellner gnome org>
Date:   Sat Mar 7 19:28:48 2020 +0100

    fileUtils: Remove some compatibility code
    
    The condition was added to keep working with the then-stable version
    of gjs. We already require a more recent version now, so the compat
    code is effectively dead.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1077

 js/misc/fileUtils.js | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)
---
diff --git a/js/misc/fileUtils.js b/js/misc/fileUtils.js
index 1abe64c2ea..e672f68bd4 100644
--- a/js/misc/fileUtils.js
+++ b/js/misc/fileUtils.js
@@ -76,19 +76,15 @@ function loadInterfaceXML(iface) {
         _ifaceResource._register();
     }
 
-    let xml = null;
     let uri = `resource:///org/gnome/shell/dbus-interfaces/${iface}.xml`;
     let f = Gio.File.new_for_uri(uri);
 
     try {
         let [ok_, bytes] = f.load_contents(null);
-        if (bytes instanceof Uint8Array)
-            xml = imports.byteArray.toString(bytes);
-        else
-            xml = bytes.toString();
+        return imports.byteArray.toString(bytes);
     } catch (e) {
         log(`Failed to load D-Bus interface ${iface}`);
     }
 
-    return xml;
+    return null;
 }