OpenSCAD: use variable "MainCase_usb_port_cover_clearance" in "UsbCover.scad", not in "MainCase.scad"

[KlausMu]

Because if USB cover and hole don't fit together, currently you have to print again the MainCase. Otherwise you only had to print again the USB cover, which is obviously much faster and needs much less filament.

[gluap]

This is a very practical suggestion - But just in case you found this the hard way and are considering reprinting the MainCase - As a hotfix I'd suggest trying to print the cover with a bit of scaling in the slicer again (until the clearance is moved to the cover).

The reason this is not straightforward to implement and might take a bit is that the clearance is generated currently by "blowing the cover up" and the clearance will have to be thoughtfully be crafted into the cover.

[KlausMu]

Yes, this is what I already did. But it worked only partly. The overall size was finally ok, but the two tongues were still too thick and I had to file them. But I succeeded without reprinting the MainCase.