Clarify deprecation of EXTRA_xxx_OPTS

The various EXTRA_xxx_OPTS variables will be removed in the Juno
development cycle, change the README to reflect the new way for
the Neutron variables.

Change-Id: Ic84da4a9b5a83e66cf0b57d643a87691f15517f0
as is_heat_enabled

this is missing, and the code assumes "heat" to be in the
enabled services list otherwise.

Change-Id: Ib0a7db04d8e38b58aca48261308e7c4d1fd43972
Integration testing preparation for Ironic

Add ability to create/register qemu vms for Ironic testing purposes

Implements bp:deprecate-baremetal-driver

Change-Id: If452438fcc0ff562531b33a36cd189b235654b48
Merge "Integration testing preparation for Ironic"
Merge "as is_heat_enabled"
Merge "Clarify deprecation of EXTRA_xxx_OPTS"
Merge branch 'master' of https://github.com/openstack-dev/devstack