Temporarily use EOL Bobcat release (#2905)

Unblock the gate while we investigate the perforamnce regressions seen
in Dalmatian (and possibly Caracal).

python-barbicanclient does not have a 2023.2-eol tag so we can't use
install from Git. Since we're not hacking on though there's no good
reason to be installing from Git, so we remove both this and
python-octaviaclient from the list.

Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

Author: stephenfin

tests/playbooks/roles/install-devstack/defaults/main.yaml

@@ -1,7 +1,7 @@
 ---
 user: "stack"
 workdir: "/home/{{ user }}/devstack"
-branch: "stable/2023.2"
+branch: "2023.2-eol"
 enable_services:
   - nova
   - glance

tests/playbooks/roles/install-devstack/templates/local.conf.j2

@@ -101,7 +101,6 @@ enable_service o-hk
 enable_service o-da
 enable_service o-api
 
-LIBS_FROM_GIT+=,python-octaviaclient
 DIB_REPOLOCATION_amphora_agent=https://github.com/openstack/octavia.git
 DIB_REPOLOCATION_octavia_lib=https://github.com/openstack/octavia-lib.git
 
@@ -121,8 +120,6 @@ enable_plugin ovn-octavia-provider https://opendev.org/openstack/ovn-octavia-pro
 # Barbican
 enable_plugin barbican ${GIT_BASE}/openstack/barbican.git {{ branch }}
 enable_service barbican-vault
-
-LIBS_FROM_GIT+=,python-barbicanclient
 {% endif %}
 
 {% if "manila" in enable_services %}