subversion: bring back from oldpackages and update to current version

Bring back Subversion from oldpackages and update to the latest version.
Create prerm script to stop subversion server and remove init script
on uninstall.

Signed-off-by: Donald Rumata <donald.rumata@gmail.com>

net/subversion/files/subversion.config

@@ -0,0 +1,3 @@
+config subversion
+	option path	'/var/local/svn'
+	option port	'3690'

net/subversion/files/subversion.init

@@ -0,0 +1,37 @@
+#!/bin/sh /etc/rc.common
+# Copyright (C) 2006-2016 OpenWrt.org
+
+START=50
+
+start_instance () {
+	local section="$1"
+	config_get path "$section" 'path'
+	config_get port "$section" 'port'
+
+	if [ ! -d "$path" ]; then
+		echo "The subversion repository (${path}) does not exist."
+		echo "Create a new repository and/or change the path in /etc/config/subversion"
+		echo
+		echo "Create a new subversion repository with:"
+		echo "        mkdir -p ${path}"
+		echo "        svnadmin create --fs-type fsfs ${path}"
+		echo
+		echo "Changing the path using UCI (default path is: /var/local/svn):"
+		echo "        uci set subversion.@[0].path="/srv/svn""
+		echo "        uci commit"
+		echo "        /etc/init.d/subversion restart"
+		return 1
+	fi
+
+	service_start /usr/bin/svnserve -d --listen-port ${port} -r ${path}
+}
+
+start() {
+	config_load 'subversion'
+	config_foreach start_instance 'subversion'
+}
+
+stop() {
+	SERVICE_SIG_STOP="INT" \
+	service_stop /usr/bin/svnserve
+}