Blazar services are not running under systemd when using DevStack

[Pierre Riteau]

DevStack recently switched to running services under systemd by default.
Blazar still installs successfully under DevStack, but blazar-api and blazar-manager services are not running under systemd and are instead printing their output to the terminal which ran stack.sh.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/465525

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/465525
Committed: https://git.openstack.org/cgit/openstack/blazar/commit/?id=b9e5a33c668eb36dd392ac029833e07dc5b5371f
Submitter: Jenkins
Branch: master

commit b9e5a33c668eb36dd392ac029833e07dc5b5371f
Author: Pierre Riteau <email address hidden>
Date: Wed May 17 12:45:44 2017 +0100

    Fix management of Blazar services by DevStack

    Calls to screen_it and screen_stop should be replaced by run_process and
    stop_process, as in Ia3843818014f7c6c7526ef3aa9676bbddb8a85ca. While
    this code worked fine with screen, DevStack now defaults to managing
    services with systemd.

    This patch ensures Blazar services are correctly launched and stopped,
    whether using systemd or screen.

    Change-Id: I99744a2e2adc46682f2ff78bdf0b09608d83d9c2
    Closes-Bug: #1691425