python: remove all 'from __future__ import print_function'

python: remove all 'from __future__ import print_function'

This made Python 2's print behave like Python 3's print().

In some cases, where we had:

   from __future__ import print_function
   """Intended module documentation..."""

this will have the side effect of making the intended module documentation
work as the actual module documentation (i.e. becoming __doc__), because
it is once again the first statement in the module.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>