When we use `tox -egenconfig`, murano configuration file
is generated incorrectly. Some options in `[keystone_authtoken]`
section are missed. This is because keystonemiddleware now use
another function for oslo_config sample generation [1].
This function now returns a smaller list of options than before
without number of deprecated options and some options required
by murano.
This patch changes entrypoint for oslo-config-generator in order
to use older keystonemiddleware's function which lists all
neccesary options
1. https://review.openstack.org/#/c/267277/
Change-Id: I61b9c102e0e07e382237f2d09206df85322cc699
Closes-Bug: #1552226
0d140a32bd