upnp: fix early crash by std::terminate

In NAP-PMP implementation, a std::thread member of
UPnPContext class is placed before member used by the thread.
This thread is run during the class initialization (ctor).
So the thread can start and access to these members when
they are not initialized.

The consequence is a std::terminate() call causing the stop
of daemon.

Fix that by moving the thread member after *ALL* used members.

Reviewed-by: Andreas Traczyk <andreas.traczyk@savoirfairelinux.com>
Change-Id: Ibb7334e653a9c80c566ffc3944c93a6ef64e0a8b

src/upnp/upnp_context.h

@@ -158,11 +158,11 @@ private:
     uint16_t chooseRandomPort(const IGD& igd, PortType type);
 
 #if HAVE_LIBNATPMP
-    std::thread pmpThread_ {};
     std::mutex pmpMutex_ {};
     std::condition_variable pmpCv_ {};
     std::shared_ptr<PMPIGD> pmpIGD_ {};
     std::atomic_bool pmpRun_ {true};
+    std::thread pmpThread_ {};
 
     void PMPsearchForIGD(const std::shared_ptr<PMPIGD>& pmp_igd, natpmp_t& natpmp);
     void PMPaddPortMapping(const PMPIGD& pmp_igd, natpmp_t& natpmp, GlobalMapping& mapping, bool remove=false) const;