add badmailfrom patch

[brdelphus]

Create a trigger to decide if your qmail-smtpd instance should respect badmailfrom regex or not
This could be very handling if you decide to have very strict rules for your qmail-smtpd that you don´t want to be applied to qmail-submission.
Usage:
add export DISABLE_BADMAILFROM=1 to your instance run file service

[sagredo-dev]

Hi, thanks for your contribution.
can I ask why are you adding the `if (!disable_badmailfrom) condition only to the badmailfrom block (flagbarfbmf) and not to the others (flagbarfbhelo, bmtok, flagbarfbmt)?

[brdelphus]

Good point Roberto. I had several strict regex lines to block receiving mail from my own domain from qmail-smtpd instance that gets external mails. but those lines were too strict to my qmail-submission instance that I'm not even interested in filtering badmailfrom. That's all