Properly initialize filesize during input buffer initialization.

patch by Ronald S. Bultje, rbultje ronald.bitfreak net

Originally committed as revision 8343 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/http.c

@@ -242,6 +242,7 @@ static int http_connect(URLContext *h, const char *path, const char *hoststr,
     s->buf_end = s->buffer;
     s->line_count = 0;
     s->off = 0;
+    s->filesize = -1;
     if (post) {
         sleep(1);
         return 0;