Printrbot hotend adapter v2

This is an adapter for using new J-Head Mk V-B hotend in the printrbot v2. Due to this hotend is smaller than others, the X-carriage hits the bed. I made this derivative for lower the pb-Xtruder-Mount-v2 and print correctly with the hotend.

NOTE: This piece may be helpful for using with another small hotend, but I can't test it.