rtpenc: remove unnecessary #include unistd.h

Originally committed as revision 24071 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rtpenc.c

@@ -24,8 +24,6 @@
 #include "internal.h"
 #include "libavutil/random_seed.h"
 
-#include <unistd.h>
-
 #include "rtpenc.h"
 
 //#define DEBUG