Wonderful... git pull on ubuntu threw me a metric B load of merge conflicts... so instead of compiling the wallet I get to figure this mess out instead. Oh well time to hit the books.
if you're talking about
https://github.com/darkcoin/darkcoin.git and
have no edits to save do:
git fetch
git checkout -f master
git reset --hard origin/master
And you'll be at the right commit (v0.11.2.16) and have a clean working directory.