fabfile: add python-nose build dependency

http://tracker.ceph.com/issues/6274 refs #6274

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #2 from dachary/master

fabfile: add python-nose build dependency
Reviewed-by: Gary Lowell <gary.lowell@inktank.com>