nut: Add USB hotplug support

usbhid-ups has the necessary information in the source, so
let's support USB hotplugging out of the box.  Takes advantage of
the procd support now in nut-server initscript.

Signed-off-by: Daniel F. Dickinson <cshored@thecshore.com>

net/nut/files/30-libhid-ups.head

@@ -0,0 +1,51 @@
+#!/bin/sh
+
+. /lib/functions.sh
+
+nut_driver_config() {
+	local cfg="$1"
+	local nomatch="$2"
+
+	config_get runas "$cfg" runas "nut"
+	config_get vendorid "$cfg" vendorid
+	config_get productid "$cfg" productid
+
+	[ "$ACTION" = "add" ] &&[ -n "$DEVNAME" ] && {
+		chmod 0660 /dev/"$DEVNAME"
+		chown ${runas:-root}:$(id -gn "${runas:-root}") /dev/"$DEVNAME"
+	}
+
+	if [ "$(printf "%04x" 0x"$pvendid")" = "$vendorid" ] && \
+		[ "$(printf "%04x" 0x"$pprodid")" = "$productid" ]; then
+			[ "$ACTION" = "add" ] && {
+				/etc/init.d/nut-server start "$cfg"
+			}
+			[ "$ACTION" = "remove" ] && {
+				/etc/init.d/nut-server stop "$cfg"
+			}
+			found=1
+	elif [ "$nomatch" = "1" ]; then
+		[ "$ACTION" = "add" ] && {
+			/etc/init.d/nut-server start "$cfg"
+		}
+		[ "$ACTION" = "remove" ] && {
+			/etc/init.d/nut-server stop "$cfg"
+		}
+	fi
+}
+
+perform_libhid_action() {
+	local vendorid productid runas
+	local pvendid pprodid found
+
+	pvendid=${PRODUCT%/*}
+	pvendid=${pvendid%/*}
+	pprodid=${PRODUCT%/*}
+	pprodid=${pprodid##*/}
+
+	config_load nut_server
+	config_foreach nut_driver_config driver 0
+	[ "$found" != "1" ] && config_foreach nut_driver_config driver 1
+}
+
+[ -n "$PRODUCT" ] && case "$PRODUCT" in