add shell account for Giuseppe (oblivian)

RT #7169, #7167

Giuseppe is a new ops member. This just adds his
account and key.

https://office.wikimedia.org/wiki/User:GLavagetto_%28WMF%29

key:
https://office.wikimedia.org/w/index.php?title=User:GLavagetto_%28WMF%29&oldid=109242

gpg: Signature made Tue 01 Apr 2014 02:32:33 AM PDT using DSA key ID C2DAEC80

gpg: Good signature from "Giuseppe Lavagetto <glavagetto@wikimedia.org>"

Change-Id: Ib79ba97b6171713c8f48292260241cce3553aa5b