Store a copy of Config in Aktualizr object

We shouldn't expect Config object to be alive
after returning from Aktualizr constructor

Signed-off-by: Eugene Smirnov <evgenii.smirnov@here.com>

src/libaktualizr/primary/aktualizr.h

@@ -166,7 +166,7 @@ class Aktualizr {
  private:
   static void systemSetup();
 
-  Config& config_;
+  Config config_;
   std::shared_ptr<INvStorage> storage_;
   std::shared_ptr<event::Channel> sig_;
   api::CommandQueue api_queue_;