Fix a flaw in the rc.subr framework reported by stephan@ where

local_rcconf would get overwritten by flags from the rc script itself.
Based on an original idea and diff from robert@, create an rc_conf
function that we add in the rc_script after the defaults daemon*
variables.
This way we can use defaults variables names in other part of the script
(when defining a specific pexp for instance).
While here, simplify setting up the default daemon variables so that we
don't need to do any substitution in rc_start.
rc scripts must include daemon variables before calling rc_conf. All
other locally modified variables (pexp, rc_reload, local additions...)
must come after.
feedback from and works for sthen@
ok robert@

src/etc/rc.d/rc.subr

@@ -1,4 +1,4 @@
-#	$OpenBSD: rc.subr,v 1.14 2010/12/13 16:06:45 ajacoutot Exp $
+#	$OpenBSD: rc.subr,v 1.15 2010/12/24 10:37:24 ajacoutot Exp $
 
 [ -z "${local_rcconf}" ] && . /etc/rc.conf
 
@@ -9,8 +9,8 @@ rc_err() {
 
 rc_start() {
 	type rc_pre >/dev/null && rc_pre
-	su -l -c ${daemon_class:-daemon} -s ${daemon_shell:-/bin/sh} \
-		${daemon_user:-root} -c "${daemon} ${daemon_flags}" >/dev/null
+	su -l -c ${daemon_class} -s ${daemon_shell} ${daemon_user} \
+		-c "${daemon} ${daemon_flags}" >/dev/null
 }
 
 rc_check() {
@@ -26,26 +26,35 @@ rc_stop() {
 	type rc_post >/dev/null && rc_post || return 0
 }
 
-rc_cmd() {
-	_name=`basename $0`
+rc_conf() {
+	[ -n "${daemon}"   ] || rc_err "$0: daemon is not set"
 
-	eval _enotsup=\${rc_${1}}
+	_name=`basename $0`
 	eval _rcflags=\${${_name}_flags}
 	eval _rcuser=\${${_name}_user}
 	eval _rcclass=\${${_name}_class}
 	eval _rcshell=\${${_name}_shell}
 
-	[ X"${_enotsup}" != X"NO" ] || rc_err "$0: $1 is not supported"
-	[ `id -u` -eq 0 -o X"$1" = "Xcheck" ] || \
-		rc_err "$0: need root privileges"
-	[ -n "${daemon}"   ] || rc_err "$0: daemon is not set"
+	[ -z "${daemon_class}" ] && daemon_class=daemon
+	[ -z "${daemon_shell}" ] && daemon_shell=/bin/sh
+	[ -z "${daemon_user}" ] && daemon_user=root
+
 	[ -n "${_rcflags}" ] && daemon_flags=${_rcflags}
-	[ -n "${_rcflags}" ] && daemon_flags=`echo ${_rcflags} | tr -s "[:space:]"`
 	[ -n "${_rcuser}"  ] && daemon_user=${_rcuser}
 	[ -n "${_rcclass}" ] && daemon_class=${_rcclass}
 	[ -n "${_rcshell}" ] && daemon_shell=${_rcshell}
-	[ -n "${pexp}"     ] || \
-		pexp="${daemon}${daemon_flags:+ ${daemon_flags}}"
+
+	daemon_flags=`echo ${daemon_flags} | tr -s "[:space:]"`
+
+	pexp="${daemon}${daemon_flags:+ ${daemon_flags}}"
+}
+
+rc_cmd() {
+	[ `id -u` -eq 0 -o X"$1" = "Xcheck" ] || \
+		rc_err "$0: need root privileges"
+
+	eval _enotsup=\${rc_${1}}
+	[ X"${_enotsup}" != X"NO" ] || rc_err "$0: $1 is not supported"
 
 	case "$1" in
 	check)