(ITS#5122) back-bdb occasionally allows bogus numeric values

[ando@sys-net.it]

Full_Name: Pierangelo Masarati
Version: since back-config
OS: irrelevant
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (193.203.230.29)
Submitted by: ando


Setting a negative number for cachesize causes an assertion in ch_calloc(); for
idlcachesize is just accepted; same for most remaining numeric data.

A neat solution would be to define ARG_UINT/ARG_ULONG, redefine types as
appropriate (now they're ints, but the negative value has no meaning or causes
crash).  There seems to be room for 8 more types in the type mask.

Not a showstopper, though.