notificationDaemon: Consider hyphens for app ID to object path translations

Some application IDs contain hyphens, which are not allowed in D-Bus object
paths, so we need to update the translation by converting them to something
that's a valid object path. This is consistent with what GApplication does.

https://bugzilla.gnome.org/show_bug.cgi?id=787902

js/ui/notificationDaemon.js

@@ -670,7 +670,7 @@ const FdoApplicationIface = '<node> \
 const FdoApplicationProxy = Gio.DBusProxy.makeProxyWrapper(FdoApplicationIface);
 
 function objectPathFromAppId(appId) {
-    return '/' + appId.replace(/\./g, '/');
+    return '/' + appId.replace(/\./g, '/').replace(/-/g, '_');
 }
 
 function getPlatformData() {