only do hotplug2 init if hotplug2 is present

only do hotplug2 init if hotplug2 is present

The current /init script unconditionally does the initialisation for
hotplug2, including mounting a new /dev. If hotplug2 isn't present, we
end up with no device nodes.

This change only does the hotplug2 init if hotplug2 is present, but
always mounts /sys.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@9411 3c298f89-4303-0410-b956-a3cf2f4a3e73