SL-17021: Fix inconsistent header definition for LLAudioEngine_OpenAL

indra/llaudio/llaudioengine_openal.h

@@ -40,7 +40,7 @@ class LLAudioEngine_OpenAL : public LLAudioEngine
 		LLAudioEngine_OpenAL();
 		virtual ~LLAudioEngine_OpenAL();
 
-        virtual bool init(const S32 num_channels, void *user_data, const std::string &app_title);
+        virtual bool init(void *user_data, const std::string &app_title);
         virtual std::string getDriverName(bool verbose);
 		virtual void allocateListener();