In PTM search assigned unimod id dosen't match real unimod id

[Nate4499]

Metamorphius assigns the modification "Decarboxylation" the Unimod id 914 and the atom count H-2 C-1 O-1. This doesn't match the entry on Unimod. And "Glu to PyroGlu" is assigned to Unimod id 28, but on Unimod it's the description for Unimod 27.

[avcarr2]

I tracked this down to incorrect hard-coding in the mods.txt file