Configuration options that are only relevant when running keystone
under eventlet (rather than Apache httpd) were moved to the
[eventlet_server] and [eventlet_server_ssl] groups in the
keystone.conf file to avoid confusion. This change updates devstack
to use the new non-deprecated group for these options.
Change-Id: I651a278d09f6a3a32b2e96fac87f1e5ea0f18c39