fixed iterator was not incremented when allocating a timer queue

src/libCom/timer/timerQueueActiveMgr.cpp

@@ -55,6 +55,7 @@ epicsTimerQueueActiveForC & timerQueueActiveMgr::allocate (
                 iter->timerQueueActiveMgrPrivate::referenceCount++;
                 return *iter;
             }
+            iter++;
         }
     }