fix mono build

MediaBrowser.Server.Mono/Native/NativeApp.cs

@@ -64,7 +64,7 @@ namespace MediaBrowser.ServerApplication.Native
             
         }
 
-        public async Task<CheckForUpdateResult> CheckForApplicationUpdate(Version currentVersion,
+        public Task<CheckForUpdateResult> CheckForApplicationUpdate(Version currentVersion,
             PackageVersionClass updateLevel,
             IInstallationManager installationManager,
             CancellationToken cancellationToken,