pin keyring to < 2.0

keyring 2.0.0 (released aug 18, 2013) contains a regression on ubuntu
regarding GnomeKeyring, see comment #5 by Pavel on:

    https://bugs.launchpad.net/ubuntu/+source/python-keyring/+bug/1197988

Change-Id: I3320da4f13cded498d6622525d56c31ae9936e0f
Closes-Bug: 1193164