Now making sure to fall-back to using the NT

challenge response for the LM challenge response field when an LM
challenge response isn't calculated

Author: Rican7

src/Robin/Ntlm/Message/NtlmV1AuthenticateMessageEncoder.php

@@ -196,20 +196,22 @@ public function encode(
             }
         }
 
-        if (null !== $lm_hash && $calculate_lm_response) {
-            $lm_challenge_response = $this->calculateLmResponse(
-                $lm_hash,
+        if (null !== $nt_hash && $calculate_nt_response) {
+            $nt_challenge_response = $this->calculateNtResponse(
+                $nt_hash,
                 $client_challenge,
                 $server_challenge_nonce
             );
         }
 
-        if (null !== $nt_hash && $calculate_nt_response) {
-            $nt_challenge_response = $this->calculateNtResponse(
-                $nt_hash,
+        if (null !== $lm_hash && $calculate_lm_response) {
+            $lm_challenge_response = $this->calculateLmResponse(
+                $lm_hash,
                 $client_challenge,
                 $server_challenge_nonce
             );
+        } else {
+            $lm_challenge_response = $nt_challenge_response;
         }
 
         // TODO: Generate an encrypted random session key