Commit da0cedce6f14f5c35e733ac345d8d862db11cd2b assumed that the
user and group for Horizon in Red Hat platforms was 'dashboard', due
to the following lines being present in openstack-dashboard.conf:
WSGIDaemonProcess dashboard
WSGIProcessGroup dashboard
Actually, based on [1], this does not mean that, and the RPM packages
do not create such user, so we should switch that to the apache user.
[1] http://modwsgi.readthedocs.io/en/latest/configuration-directives/WSGIDaemonProcess.html
Change-Id: I52766ac0521951cc8c857e51a61823410585bed5
e1e0a1b56c