PARTIAL TAKE 920426 - xlog recovery failure on pre-v2-log xfs

[Timothy Shimmin <tes@xxxxxxxxxxxxxxxxxxxxxxx>]

Fix problem for case where v1 log is created on a recent xfs kernel
(from Feb 27, 2004 onwards) and its a dirty log (not a clean unmount)
and now trying to replay this log on an old xfs kernel
(prior to Dec 2, 2002 when v2 logs went in). 

fix up h_len for v1 logs

Date:  Tue Aug 31 06:08:52 PDT 2004
Workarea:  snort.melbourne.sgi.com:/home/tes/isms/xfs-linux
Inspected by:  nathans@xxxxxxx

The following file(s) were checked into:
  bonnie.engr.sgi.com:/isms/xfs-kern/xfs-linux


Modid:  xfs-linux:xfs-kern:178055a
xfs_log.c - 1.300