lavf: remove unnecessary inclusions of unistd.h

These files do not use anything provided by unistd.h.
Signed-off-by: Mans Rullgard <mans@mansr.com>

libavformat/http.c

@@ -21,7 +21,6 @@
 
 #include "libavutil/avstring.h"
 #include "avformat.h"
-#include <unistd.h>
 #include "internal.h"
 #include "network.h"
 #include "http.h"

libavformat/os_support.c

@@ -57,7 +57,6 @@ int ff_win32_open(const char *filename_utf8, int oflag, int pmode)
 
 #if CONFIG_NETWORK
 #include <fcntl.h>
-#include <unistd.h>
 #if !HAVE_POLL_H
 #include <sys/time.h>
 #if HAVE_WINSOCK2_H

libavformat/rtpdec_h264.c

@@ -39,7 +39,6 @@
 #include "avformat.h"
 #include "mpegts.h"
 
-#include <unistd.h>
 #include "network.h"
 #include <assert.h>
 

libavformat/rtpproto.c

@@ -31,7 +31,6 @@
 #include "rtpdec.h"
 #include "url.h"
 
-#include <unistd.h>
 #include <stdarg.h>
 #include "internal.h"
 #include "network.h"