Merge pull request #513 from constZinovyev/fix-vkrequest-retain-cycle

Fix retain cycle between VKRequest and VKError

library/Source/Core/VKRequest.m

@@ -429,6 +429,7 @@ void vksdk_dispatch_on_main_queue_now(void(^block)(void)) {
                 }
             }
         };
+        self.error = nil;
     } else {
         block = ^{
             if (self.completeBlock) {