ItemProjector : Fix checking for actual "machineId" NBT tag instead of checking for any NBT data

[LelouBil]

I was trying to make a modpack and was stumbling upon a very weird crash.
I narrowed it down to this :
There was a mod in my list (I still don't know which) that was adding a "temperature" NBT tag to the ItemProjector stack.
When entering ItemProjector.addInformation(), getMachineId returned 0 (the default value since the NBT tag "machineId" was not present) instead of returning -1.

This was because getMachineId only checks if there is any NBT data at all, and not if the tag "machineid" is set.

This simple addition will fix that.

Side note, I still don't know what is adding the mysterious "temperature" tag to the item.

[voidsong-dragonfly]

Putting this on hold until new code gets merged, as it rolls over quite a few things with a steamroller including the projector.