Fix deadlock issue with mingw in async logger

include/spdlog/details/mpmc_blocking_q.h

@@ -32,29 +32,24 @@ public:
 
     // try to enqueue and block if no room left
     void enqueue(T &&item)
-    {
     {        
         std::unique_lock<std::mutex> lock(queue_mutex_);
         pop_cv_.wait(lock, [this] { return !this->q_.full(); });
         q_.push_back(std::move(item));        
-        }
 		push_cv_.notify_one();
     }
 
     // enqueue immediately. overrun oldest message in the queue if no room left.
     void enqueue_nowait(T &&item)
-    {
     {        
         std::unique_lock<std::mutex> lock(queue_mutex_);
         q_.push_back(std::move(item));       
-        }
 		push_cv_.notify_one();
     }
 
     // try to dequeue item. if no item found. wait upto timeout and try again
     // Return true, if succeeded dequeue item, false otherwise
     bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
-    {
     {        
 		std::unique_lock<std::mutex> lock(queue_mutex_);
 		if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); }))
@@ -62,7 +57,6 @@ public:
 			return false;
 		}
 		q_.pop_front(popped_item);        
-        }
         pop_cv_.notify_one();
         return true;
     }