Fixing a bug where READONLY is run before AUTH. Causes MOVED errors when...

Fixing a bug where READONLY is run before AUTH. Causes MOVED errors when reconnecting to Clustered Slaves. (#1367)

src/StackExchange.Redis/PhysicalBridge.cs

@@ -1199,6 +1199,11 @@ private WriteResult WriteMessageToServerInsideWriteLock(PhysicalConnection conne
                 SelectDatabaseInsideWriteLock(connection, message);
 
                 if (!connection.TransactionActive)
+                {
+                    // If we are executing AUTH, it means we are still unauthenticated
+                    // Setting READONLY before AUTH always fails but we think it succeeded since
+                    // we run it as Fire and Forget. 
+                    if (cmd != RedisCommand.AUTH)
                     {
                         var readmode = connection.GetReadModeCommand(isMasterOnly);
                         if (readmode != null)
@@ -1208,7 +1213,7 @@ private WriteResult WriteMessageToServerInsideWriteLock(PhysicalConnection conne
                             readmode.SetRequestSent();
                             IncrementOpCount();
                         }
-
+                    }
                     if (message.IsAsking)
                     {
                         var asking = ReusableAskingCommand;