serverContext: collapse destroyAllTransports() into shutdown()

src/server/serverContext.cpp

@@ -346,7 +346,7 @@ void ServerContextImpl::shutdown()
     }
 
     // this will also destroy all channels
-    destroyAllTransports();
+    _transportRegistry.clear();
 
     // drop timer queue
     LEAK_CHECK(_timer, "_timer")
@@ -360,12 +360,6 @@ void ServerContextImpl::shutdown()
     _runEvent.signal();
 }
 
-void ServerContextImpl::destroyAllTransports()
-{
-    // now clear all (release)
-    _transportRegistry.clear();
-}
-
 void ServerContext::printInfo(int lvl)
 {
     printInfo(cout, lvl);