Remove a useless directive.

Originally committed as revision 14645 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/log.c

@@ -38,7 +38,6 @@ void av_log_default_callback(void* ptr, int level, const char* fmt, va_list vl)
     if(print_prefix && avc) {
         fprintf(stderr, "[%s @ %p]", avc->item_name(ptr), ptr);
     }
-#define fprintf please_use_av_log
 
     print_prefix= strstr(fmt, "\n") != NULL;