Another NPE fix

app/src/main/java/chat/rocket/android/push/FirebaseTokenService.kt

@@ -35,17 +35,19 @@ class FirebaseTokenService : FirebaseInstanceIdService() {
         // default push gateway. We should register this project's own project sender id into it.
         val gcmToken = InstanceID.getInstance(this)
                 .getToken(getString(R.string.gcm_sender_id), GoogleCloudMessaging.INSTANCE_ID_SCOPE, null)
-        val currentServer = getCurrentServerInteractor.get()!!
-        val client = factory.create(currentServer)
+        val currentServer = getCurrentServerInteractor.get()
+        val client = currentServer?.let { factory.create(currentServer) }
 
         gcmToken?.let {
             localRepository.save(LocalRepository.KEY_PUSH_TOKEN, gcmToken)
-            launch {
-                try {
-                    Timber.d("Registering push token: $gcmToken for ${client.url}")
-                    client.registerPushToken(gcmToken)
-                } catch (ex: RocketChatException) {
-                    Timber.e(ex)
+            client?.let {
+                launch {
+                    try {
+                        Timber.d("Registering push token: $gcmToken for ${client.url}")
+                        client.registerPushToken(gcmToken)
+                    } catch (ex: RocketChatException) {
+                        Timber.e(ex)
+                    }
                 }
             }
         }