Fix-up any code that uses butler.repository

See https://community.lsst.org/t/access-to-root-in-butler/991
When running constructBias.py in lsst_apps w_2016_34 I get the error:
AttributeError in map: 'Butler' object has no attribute 'repository'
The source of the error is probably
https://github.com/lsst/pipe_drivers/blob/master/python/lsst/pipe/drivers/constructCalibs.py#L585
All code that uses butler.repository should be fixed. If that's too much work possibly the ticket could get changed to fix constructCalibs only for now.