avoid an extra malloc

  flen = ftp->file?strlen(ftp->file):0; /* file is "raw" already */

  dlen = strlen(path)-flen;

  if(dlen) {

    ftp->prevpath = malloc(dlen + 1);

    if(!ftp->prevpath) {

      free(path);

      return CURLE_OUT_OF_MEMORY;

    }

    memcpy(ftp->prevpath, path, dlen);

    ftp->prevpath = path;

    if(flen)

      /* if 'path' is not the whole string */

      ftp->prevpath[dlen]=0; /* terminate */

    infof(data, "Remembering we are in dir %s\n", ftp->prevpath);

  }

  else

  else {

    ftp->prevpath = NULL; /* no path */

    free(path);

  }

  /* free the dir tree and file parts */

  freedirs(ftp);