pupnp: dispatch instead of post to avoid deadlock

Gitlab: #631
Change-Id: I17b5e5edd7bf4d7a7ce26d766146d796d41c8889

src/upnp/protocol/pupnp/pupnp.cpp

@@ -619,7 +619,7 @@ void
 PUPnP::requestMappingRemove(const Mapping& mapping)
 {
     // Send remove request using the matching IGD
-    ioContext->dispatch([w = weak(), mapping] {
+    ioContext->post([w = weak(), mapping] {
         if (auto upnpThis = w.lock()) {
             // Abort if we are shutting down.
             if (not upnpThis->isRunning())