Use new packet reading API, fixes a memory leak.

patch by Zdenek Kabelac, zdenek.kabelac gmail com

Originally committed as revision 18728 to svn://svn.ffmpeg.org/ffmpeg/trunk

tools/pktdumper.c

@@ -107,11 +107,14 @@ int main(int argc, char **argv)
             write(fd, pkt.data, pkt.size);
             close(fd);
         }
+        av_free_packet(&pkt);
         pktnum++;
         if (maxpkts && (pktnum >= maxpkts))
             break;
     }
 
+    av_close_input_file(fctx);
+
     while (donotquit)
         sleep(60);