Make Server CONFIG_DRIVE property a boolean
Make Server CONFIG_DRIVE property a boolean

There's no reason for CONFIG_DRIVE to be a string.  It only accepts a
boolean.

Related change in python-novaclient:
https://review.openstack.org/#/c/91169

Change-Id: I2ff588537fbe72fefed0163b69e68c4f484a38e7

srznew/heat,redhat-openstack/heat,openstack/heat,rh-s/heat,pratikmallya/heat,srznew/heat,noironetworks/heat,takeshineshiro/heat,rdo-management/heat,miguelgrinberg/heat,jasondunsmore/heat,dragorosson/heat,miguelgrinberg/heat,pshchelo/heat,dims/heat,pratikmallya/heat,maestro-hybrid-cloud/heat,dims/heat,takeshineshiro/heat,noironetworks/heat,pshchelo/heat,cwolferh/heat-scratch,gonzolino/heat,dragorosson/heat,rh-s/heat,cryptickp/heat,steveb/heat,cwolferh/heat-scratch,redhat-openstack/heat,jasondunsmore/heat,gonzolino/heat,rdo-management/heat,cryptickp/heat,openstack/heat,maestro-hybrid-cloud/heat,steveb/heat