misc: only check for app updates on windows

Change-Id: I508300446e5c8891bb018af0b0c42de4309685c6

src/app/MainApplicationWindow.qml

@@ -233,7 +233,7 @@ ApplicationWindow {
             windowSettingsLoaded = true;
 
             // Quiet check for updates on start if set to.
-            if (Qt.platform.os.toString() !== "osx") {
+            if (Qt.platform.os.toString() === "windows") {
                 if (UtilsAdapter.getAppValue(Settings.AutoUpdate)) {
                     UpdateManager.checkForUpdates(true);
                     UpdateManager.setAutoUpdateCheck(true);