Fixed Xeno-Arch Chem-Dispenser

Admin request as well as overwhelming support on a thread.
http://baystation12.net/forums/viewtopic.php?f=5&t=9306

I've seen Admins fix this everytime someone asks so going to just save them the trouble.
Merge pull request #4281 from Ccomp5950/chem_fix

Fixed Xeno-Arch Chem-Dispenser