tdb corruption with "use mmap=false"

[Jeremy Allison]

Don,

	After staring at this bloody thing for 7 hours today,
Andrew fixed it in less than 1 hour (typical :-).

Anyway, the tdb fixes for this are in 2.2.2 and HEAD, and
now use pread/pwrite on HPUX so should be faster.....

Please re-check out and confirm it's fixed.

Thanks,

	Jeremy.