[bifrost] Force Bifrost to use the correct git branch

Bifrost decides on the branches to use by itself.
Early in the cycle, they are often not set correctly and may
break our CI.
This patch ensures we force Bifrost to use the expected branches,
making us independent of Bifrost getting fixed.

Change-Id: I33dbca927062284fd7a06ab6db732dd5e2219c40
(cherry picked from commit 0e3b29c)

Author: yoctozepto

docker/bifrost/bifrost-base/Dockerfile.j2

@@ -42,6 +42,8 @@ RUN echo " " && \
 {%- endif %}
     bash -c './scripts/env-setup.sh && \
     ansible-playbook -vvvv -i /bifrost/playbooks/inventory/target /bifrost/playbooks/install.yaml \
+    -e git_branch={{ openstack_branch_slashed }} \
+    -e ipa_upstream_release={{ openstack_branch }} \
     -e @/tmp/build_arg.yml && \
 {%- if base_package_type == 'deb' %}
     apt-get clean && rm -rf /var/lib/apt/lists/*'

kolla/image/build.py

@@ -663,6 +663,8 @@ def __init__(self, conf):
             self.debian_arch = 'amd64'
         self.images = list()
         self.openstack_release = conf.openstack_release
+        self.openstack_branch = conf.openstack_branch
+        self.openstack_branch_slashed = conf.openstack_branch_slashed
         self.docker_healthchecks = conf.docker_healthchecks
         rpm_setup_config = ([repo_file for repo_file in
                              conf.rpm_setup_config if repo_file is not None])
@@ -897,6 +899,9 @@ def create_dockerfiles(self):
                       'install_type': self.install_type,
                       'namespace': self.namespace,
                       'openstack_release': self.openstack_release,
+                      'openstack_branch': self.openstack_branch,
+                      'openstack_branch_slashed':
+                          self.openstack_branch_slashed,
                       'tag': self.tag,
                       'maintainer': self.maintainer,
                       'kolla_version': kolla_version,