remove double lock

src/PlugIn.cpp

@@ -809,7 +809,6 @@ void PlugIn::updateSequence(std::shared_ptr<aman::AircraftSequence>& sequence) {
 
         if (false == found) {
             /* delete the forced runway selection */
-            std::lock_guard guard(this->m_updateQueueLock);
             auto selected = this->m_selectedRunway.find(it->first);
             if (this->m_selectedRunway.end() != selected)
                 this->m_selectedRunway.erase(selected);