Robo3D fan mount mod for E3D V6 hotend

Installing the E3D V6 extruder on the Robo3D makes it necessary to swap out the original fan-mount with a 3D printed mount in order to allow for the greater bulk of the new extruder. I made some slight changes to tonycstech's file, as I found the fan-mount designed for the V5 did not have enough room for this latest generation E3D extruder.