upnp: fix waiting while holding a lock

Blocking function (sleep) called when inside locked region.
This patch uses a move-in-temporary idiom to prevent that.
Was detected by Coverity scan.

Change-Id: I7ab74001c3d9de11e1d95b5e4a1c1bd0a8dce8c9
Reviewed-by: Olivier SOLDANO <olivier.soldano@savoirfairelinux.com>

src/upnp/upnp_context.cpp

@@ -138,9 +138,13 @@ UPnPContext::UPnPContext()
                     pmp_igd->clearAll_ = false;
                     pmp_igd->toRemove_.clear();
                 } else if (not pmp_igd->toRemove_.empty()) {
-                    for (auto& m : pmp_igd->toRemove_)
-                        PMPaddPortMapping(*pmp_igd, natpmp, m, true);
+                    decltype(pmp_igd->toRemove_) removed = std::move(pmp_igd->toRemove_);
                     pmp_igd->toRemove_.clear();
+                    lk.unlock();
+                    for (auto& m : removed) {
+                        PMPaddPortMapping(*pmp_igd, natpmp, m, true);
+                    }
+                    lk.lock();
                 }
                 auto mapping = pmp_igd->getNextMappingToRenew();
                 if (mapping and mapping->renewal_ < now)