openvpn: quote parameters to --push in openvpn config file

OpenVPN requires arguments to --push to be enclosed in double quotes.
One set of quotes is stripped when the UCI config is parsed.
Change append_params() of openvpn.init to enclose push parameters in
double quotes.

Unquoted push parameters do not cause errors in OpenVPN 2.3,
but OpenVPN 2.4 fails to start with unquoted push parameters.

Fixes: FS#290.

Signed-off-by: Magnus Kroken <mkroken@gmail.com>

package/network/services/openvpn/files/openvpn.init

@@ -42,7 +42,8 @@ append_params() {
 		config_get v "$s" "$p"
 		IFS="$LIST_SEP"
 		for v in $v; do
-			[ -n "$v" ] && append_param "$s" "$p" && echo " $v" >> "/var/etc/openvpn-$s.conf"
+			[ -n "$v" ] && [ "$p" != "push" ] && append_param "$s" "$p" && echo " $v" >> "/var/etc/openvpn-$s.conf"
+			[ -n "$v" ] && [ "$p" == "push" ] && append_param "$s" "$p" && echo " \"$v\"" >> "/var/etc/openvpn-$s.conf"
 		done
 		unset IFS
 	done