postfix: create or update aliases.db when using systemd

aliases.db should be created by postinstall script, but failed since
queue_directory is not includes root dir ${D}:
    ------
    |newaliases: fatal: chdir /var/spool/postfix: No such file or directory
    ------
initscript will recall newaliases before start postfix daemon, the similar
method, which run aliasesdb to create aliases.db when using systemd, is
introduced to fix this issue.

Signed-off-by: Roy.Li <rongqing.li@windriver.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>

meta-networking/recipes-daemons/postfix/files/aliasesdb

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+ALIASESDB_STAMP=/var/lib/misc/postfix.aliasesdb-stamp
+
+make_aliasesdb() {
+        if [ "$(/usr/sbin/postconf -h alias_database)" = "hash:/etc/aliases" ]
+        then
+                # /etc/aliases.db may be used by other MTA, make sure nothing
+                # has touched it since our last newaliases call
+                [ /etc/aliases -nt /etc/aliases.db ] ||
+                        [ "$ALIASESDB_STAMP" -nt /etc/aliases.db ] ||
+                        [ "$ALIASESDB_STAMP" -ot /etc/aliases.db ] || return 0
+                /usr/bin/newaliases
+                touch -r /etc/aliases.db "$ALIASESDB_STAMP"
+        else
+                /usr/bin/newaliases
+        fi
+}
+
+make_aliasesdb

meta-networking/recipes-daemons/postfix/files/postfix.service

@@ -6,6 +6,7 @@ Conflicts=sendmail.service exim.service
 [Service]
 Type=forking
 PIDFile=/var/spool/postfix/pid/master.pid
+ExecStartPre=-/usr/libexec/postfix/aliasesdb
 ExecStart=/usr/sbin/postfix start
 ExecReload=/usr/sbin/postfix reload
 ExecStop=/usr/sbin/postfix stop

meta-networking/recipes-daemons/postfix/postfix.inc

@@ -22,6 +22,7 @@ SRC_URI = "ftp://ftp.porcupine.org/mirrors/postfix-release/official/postfix-${PV
 	   file://postfix \
 	   file://internal_recipient \
 	   file://postfix.service \
+	   file://aliasesdb \
 	   "
 
 S = "${WORKDIR}/postfix-${PV}"
@@ -149,6 +150,8 @@ do_install () {
 	install -m 0644 ${WORKDIR}/postfix.service ${D}${systemd_unitdir}/system
 	sed -i 's,/usr/sbin/,${sbindir}/,g' ${D}${systemd_unitdir}/system/postfix.service
 
+	install -m 0755 ${WORKDIR}/aliasesdb ${D}${exec_prefix}/libexec/postfix/
+
 	install -m 770 -d ${D}${localstatedir}/spool/postfix
 	chown postfix:postfix ${D}${localstatedir}/spool/postfix
 	chown postfix:postfix ${D}${localstatedir}/lib/postfix