TAKE - ensure log recovery does not look at data outside log

[Steve Lord <lord@xxxxxxx>]

Thanks to ASANO Masahiro for finding the problem, I used a different
fix than his suggestion, this version will avoid reading extra data
off the disk, possibly off the end of a device if an external log is
used.

Date:  Fri Sep 28 10:40:46 PDT 2001
Workarea:  jen.americas.sgi.com:/src/lord/xfs-linux.2.4

The following file(s) were checked into:
  bonnie.engr.sgi.com:/isms/slinx/2.4.x-xfs


Modid:  2.4.x-xfs:slinx:103579a
linux/fs/xfs/xfs_log_recover.c - 1.212
        - Avoid scanning off the end of the log when looking for the head and
          tail.