bf_resize issues

[Clint Adams]

I just ran into my first 'cannot allocate memory' problem, and so I
attempted to run bf_resize.

It failed because of 'set -e' and the return code of 'egrep'; I added a
'|| true' after the egrep, and it performed as intended.

Since this egrep will always fail in my case, I suggest that this be
made more resilient.

I would prefer, however, that no DB_CONFIG file be created or modified,
and instead that the "resizing" be performed automatically and
transparently by the main bogofilter binary.