fix unreliable sleep

After a certain update I had my laptop wake from sleep as soon as
it went to sleep. it turns out that it's USB. I thought I had unloaded
the USB modules in /etc/pm/config.d/modules but it looks like ubuntu is
now compiling them into the kernel.

This script that I found while looking into how to work around not being
able to unload the usb modules uses a sysfs interface to unbind the USB
busses from the drivers and then re-bind them after sleep. it seems to
have solved my issue after using it for a few days.