alsa: fix possible threading issue

An std::thread, ctor constructer, must be the last members in a class to be sure
that all previous members are initialized in class ctor before to run the thread
itself.
This may fixes random issues seen with others member accesses.

Change-Id: I7ceb0cf522236411f4a2faa34ff4f32eae0e4c13
Tuleap: #171

src/media/audio/alsa/alsalayer.cpp

@@ -44,12 +44,11 @@ class AlsaThread {
     bool isRunning() const;
 
 private:
-        void run();
-
     NON_COPYABLE(AlsaThread);
-        std::thread thread_;
+    void run();
     AlsaLayer* alsa_;
     std::atomic<bool> running_;
+    std::thread thread_;
 };
 
 AlsaThread::AlsaThread(AlsaLayer *alsa)