Use constexpr to initialize constant in class definition

indra/media_plugins/gstreamer010/media_plugin_gstreamer010.cpp

@@ -76,7 +76,7 @@ class MediaPluginGStreamer010 : public MediaPluginBase
 	bool play(double rate);
 	bool getTimePos(double &sec_out);
 
-	static const double MIN_LOOP_SEC = 1.0F;
+	static constexpr double MIN_LOOP_SEC = 1.0F;
 
 	bool mIsLooping;