COPKGManager: craete directory /tmp/.opkg on opkg manager init

This directory can be useful for usage in opkg config as cache directory

option cache /tmp/.opkg

src/gui/opkg_manager.cpp

@@ -87,6 +87,7 @@ COPKGManager::COPKGManager()
 	list_installed_done = false;
 	list_upgradeable_done = false;
 	expert_mode = false;
+	CFileHelpers::createDir("/tmp/.opkg");
 }
 
 COPKGManager::~COPKGManager()