Update to exim-4.22:

• IPv6 bug fix incorporated.
• Catch up with changes in makefiles.
• Make portlint happier with respect to DOCSDIR, INFO and spaces.
• Use the new INFO macro.
• Use PATCHFILES instead of patching by hand, now that we don't support the non-ACL exiscan patch.

This release fixes a few last minute release mistakes from 4.21.

PR: ports/55701
Submitted by: Oliver Eikemeier <eikemeier@fillmore-labs.com>