db/upnp/Device: use ContentDirectoryDescriptor's move operator

src/db/upnp/Device.hxx

@@ -85,6 +85,10 @@ public:
 	UPnPDevice(const std::string &url, const char *description);
 
 	UPnPDevice() : ok(false) {}
+
+	UPnPDevice(const UPnPDevice &) = delete;
+	UPnPDevice(UPnPDevice &&) = default;
+	UPnPDevice &operator=(UPnPDevice &&) = default;
 };
 
 #endif /* _UPNPDEV_HXX_INCLUDED_ */

src/db/upnp/Discovery.cxx

@@ -82,13 +82,7 @@ UPnPDeviceDirectory::discoExplorer()
 		}
 
 		const ScopeLock protect(mutex);
-#if defined(__clang__) || GCC_CHECK_VERSION(4,8)
-		auto e = directories.emplace(tsk->deviceId, d);
-#else
-		auto e = directories.insert(std::make_pair(tsk->deviceId, d));
-#endif
-		if (!e.second)
-			e.first->second = d;
+		directories[std::move(tsk->deviceId)] = std::move(d);
 
 		delete tsk;
 	}

src/db/upnp/Discovery.hxx

@@ -65,6 +65,8 @@ class UPnPDeviceDirectory {
 	 */
 	class ContentDirectoryDescriptor {
 	public:
+		ContentDirectoryDescriptor() = default;
+
 		ContentDirectoryDescriptor(const std::string &url,
 					   const char *description,
 					   time_t last, int exp)