mail/mailman: repair incomplete UCL conversion of pkg-message.in

There are parts of the install message that are also relevant on
updates, but were missed. Add them, and bump PORTREVISION.

Failure-inducing commit:

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r508882 | mat | 2019-08-14 00:29:42 +0200 (Wed, 14 Aug 2019) | 2 lines

onvert to UCL & cleanup pkg-message (categories l-m)

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mail/mailman/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	mailman
 DISTVERSION=	2.1.29
-PORTREVISION=	6
+PORTREVISION=	7
 CATEGORIES=	mail
 MASTER_SITES=	GNU \
 		SF/${PORTNAME}/Mailman%202.1%20%28stable%29/${PORTVERSION} \
@@ -190,7 +190,6 @@ post-patch-HTDIG-on:
 		-e 's#/opt/www/htdig/bin#${LOCALBASE}/bin#' \
 		${WRKSRC}/Mailman/Cgi/remote?mmsearch
 
-
 .if ${PORT_OPTIONS:MPOSTFIX}
 pre-configure:
 	${ECHO} "MTA = 'Postfix'" >> ${WRKSRC}/Mailman/mm_cfg.py.dist.in

mail/mailman/files/pkg-message.in

@@ -53,6 +53,24 @@ In order to make private archives searchable with namazu2, you need
 to copy or link %%LOCALBASE%%/libexec/namazu.cgi to
 %%MAILMANDIR%%/archives/private/<ML_name>/ and configure .namazurc.
 Refer to %%LOCALBASE%%/etc/namazu/namazurc.sample.
+EOM
+}
+{ type: upgrade
+  message <<EOM
+==========================================
+WARNING ATTENTION DANGER ATTENTION WARNING
+==========================================
+
+mail/mailman requires proper directory permissions to run; but due to
+pkg 1.4.1 or libarchive bugs, directory permissions can not be created
+properly.
+
+If you installed mailman with pkg -I, --no-script or --no-install-scripts,
+you MUST(!) run the post-install script now, as root:
+
+env "PKG_PREFIX=%%PREFIX%%" sh \
+    %%MAILMANDIR%%/bin/FreeBSD-post-install x POST-INSTALL
+
 EOM
 }
 { type: upgrade