avformat/fifo_test: remove network.h include

It's not needed, and fixes compilation with network disabled.
Signed-off-by: James Almer <jamrial@gmail.com>

libavformat/fifo_test.c

@@ -20,12 +20,13 @@
  */
 
 #include <stdlib.h>
+
 #include "libavutil/opt.h"
 #include "libavutil/time.h"
 #include "libavutil/avassert.h"
-#include "libavformat/avformat.h"
-#include "libavformat/url.h"
-#include "libavformat/network.h"
+
+#include "avformat.h"
+#include "url.h"
 
 /* Implementation of mock muxer to simulate real muxer failures */