Gate: Fix version of ansible deployed via dev-deploy

This pins the version of ansible deployed via the makefile
dev-deploy directives to the version used in zuul.  This was
causing issues with docker, as make dev-deploy setup-host was
deploying ansible 2.6. Ansible 2.6 introduces a new flag to the
docker_container module (init) that is incompatible with our
current roles, which resulted in observed failures in osh-infra
and osh

Change-Id: Ibc885b53bce77eb36817024b21efb0e99865f690

tools/gate/devel/start.sh

@@ -59,8 +59,12 @@ function ansible_install {
   # https://github.com/python-cmd2/cmd2/issues/421
   sudo -H -E pip install --no-cache-dir --upgrade "cmd2<=0.8.7"
   sudo -H -E pip install --no-cache-dir --upgrade pyopenssl
+  # NOTE(srwilkers): Pinning ansible to 2.5.5, as pip installs 2.6 by default.
+  # 2.6 introduces a new command flag (init) for the docker_container module
+  # that is incompatible with what we have currently. 2.5.5 ensures we match
+  # what's deployed in the gates
+  sudo -H -E pip install --no-cache-dir --upgrade "ansible==2.5.5"
   sudo -H -E pip install --no-cache-dir --upgrade \
-    ansible \
     ara \
     yq
 }

tools/images/kubeadm-aio/Dockerfile

@@ -70,7 +70,12 @@ RUN set -ex ;\
     hash -r ;\
     pip --no-cache-dir install setuptools ;\
     pip --no-cache-dir install kubernetes ;\
-    pip --no-cache-dir install ansible ;\
+
+    # NOTE(srwilkers): Pinning ansible to 2.5.5, as pip installs 2.6 by default.
+    # 2.6 introduces a new command flag (init) for the docker_container module
+    # that is incompatible with what we have currently. 2.5.5 ensures we match
+    # what's deployed in the gates
+    pip --no-cache-dir install "ansible==2.5.5" ;\
     for BINARY in kubectl kubeadm; do \
       curl -sSL -o /usr/bin/${BINARY} \
         https://storage.googleapis.com/kubernetes-release/release/${KUBE_VERSION}/bin/linux/amd64/${BINARY} ;\