fixed crashes when exporting as OGG and output file can't be created or OGG encoding settings are wrong

git-svn-id: https://lmms.svn.sf.net/svnroot/lmms/trunk/lmms@1664 0778d3d1-df1d-0410-868b-ea421aaaa00d

include/audio_file_device.h

@@ -54,7 +54,6 @@ public:
 
 protected:
 	Sint32 writeData( const void * _data, Sint32 _len );
-	void seekToBegin( void );
 
 	inline bool useVBR( void ) const
 	{

include/audio_file_ogg.h

@@ -80,7 +80,7 @@ private:
 	inline Sint32 writePage( void );
 
 
-
+	bool m_ok;
 	ch_cnt_t m_channels;
 	sample_rate_t m_rate;