Build Octavia from StackHPC fork

This is necessary to fix issues with TLS-terminated Octavia load
balancers following our bump of pyOpenSSL [1] because of the removal of
load_pkcs12 [2].

[1] stackhpc/requirements#20
[2] https://bugs.launchpad.net/octavia/+bug/2042787

Author: priteau

etc/kayobe/kolla.yml

@@ -155,6 +155,10 @@ kolla_sources:
     type: git
     location: https://github.com/stackhpc/networking-mlnx
     reference: stackhpc/{{ openstack_release }}
+  octavia-base:
+    type: git
+    location: https://github.com/stackhpc/octavia.git
+    reference: stackhpc/{{ openstack_release }}
 
 ###############################################################################
 # Kolla image build configuration.

releasenotes/notes/fix-octavia-tls-terminated-pkcs12-4f7e32a6f5ca0143.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fixes creation and failover of Octavia TLS-terminated load balancers when
+    storing the certificate and key as a PKCS12 bundle in Barbican.