postfix: update daemon_directory in main.cf_2.0

daemon_directory is set to /usr/lib/postfix which causes daemon postfix
fails to start on 64 bits target if enable multilib. Set daemon_directory
with libexecdir to fix it.

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>

meta-networking/recipes-daemons/postfix/files/main.cf_2.0

@@ -30,7 +30,7 @@ queue_directory = /var/spool/postfix
 mail_spool_directory = /var/spool/mail
 readme_directory = no
 command_directory = /usr/sbin
-daemon_directory = /usr/lib/postfix
+daemon_directory = @LIBEXECDIR@
 mail_owner = postfix
 setgid_group = postdrop
 unknown_local_recipient_reject_code = 450

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

@@ -142,6 +142,8 @@ do_install () {
     mv ${D}${sysconfdir}/postfix/main.cf ${D}${sysconfdir}/postfix/sample-main.cf
     install -d ${D}${sysconfdir}/init.d
     install -m 644 ${WORKDIR}/main.cf_2.0 ${D}${sysconfdir}/postfix/main.cf
+    sed -i 's#@LIBEXECDIR@#${libexecdir}#' ${D}${sysconfdir}/postfix/main.cf
+
     install -m 755 ${WORKDIR}/postfix ${D}${sysconfdir}/init.d/postfix
     install -m 644 ${WORKDIR}/internal_recipient ${D}${sysconfdir}/postfix/internal_recipient