libxvid_rc: fix leaks in ff_xvid_rate_control_init()

Fixes CID733796 Part1
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/libxvid_rc.c

@@ -57,6 +57,8 @@ int ff_xvid_rate_control_init(MpegEncContext *s){
 
         if (write(fd, tmp, strlen(tmp)) < 0) {
             av_log(NULL, AV_LOG_ERROR, "Error %s writing 2pass logfile\n", strerror(errno));
+            av_free(tmp_name);
+            close(fd);
             return AVERROR(errno);
         }
     }