Fix library includes for config generator

Fix library includes for config generator

Noticed today while working on fixing issues
with the config generator that oslo_policy
had been added in the wrong location for
pulling the config options in to the config
generator.

This fix moves the items that had been put in
oslo.config.generator.rc but were missing in generate_sample.sh
over to the appropriate location.  I also removed the option for
importing additional libraries in oslo.config.generator.rc
given that it will not work.

I am still working on a longer term solution, but
we really should get this fixed so we can generate sample
config files again.

Change-Id: I2c14c1acc49d68305dca5a3dedc686ab07ed2088