Sync sample config file generator with Oslo

The sample generator tool in Oslo is located in tools/config therefore
this patch moves the files in tools/conf to tools/config. The reason
Oslo chose 'config' is because the generator.py module is located in
the openstack.common.config package and update.py looks for the
corresponding directory in tools when it syncs the 'config' package.

./update.sh --module config --base nova --dest-dir $NOVA_HOME --nodep

Since every thing moved to tools/config, changes had to happen on
the tox.ini file and check_update.sh

Change-Id: Icbd467888cc7f16fa3694ed2b93548d0285461b5