MFH: r427533

mail/py-milter: fix runtime crash; pass on MAINTAINER

• Import patch to resolve crash during IPv6 connection handling. Submitter has coordinated fix with upstream; it can be removed next update.
• Pass on MAINTAINER to from ports@ to submitter.
• While here, move DIST_SUBDIR to appease portlint.

PR: 214317
Submitted by: schmidt@ze.tum.de
Approved by: ports-secteam (runtime fix blanket)