Support installing specific version of docker

Change-Id: I12015c28f6f8ffc125097a14514a6a90a20cf35b
(cherry picked from commit f8e786f0d5)

.gitreview

@@ -2,3 +2,4 @@
 host=review.opendev.org
 port=29418
 project=openstack/devstack-plugin-container.git
+defaultbranch=stable/zed

devstack/lib/docker

@@ -61,6 +61,7 @@ function install_docker {
         arch=$(dpkg --print-architecture)
     fi
     if is_ubuntu; then
+        apt_get install apparmor
         if [[ ${dist_version} == 'trusty' ]]; then
             if uname -r | grep -q -- '-generic' && dpkg -l 'linux-image-*-generic' | grep -qE '^ii|^hi' 2>/dev/null; then
                 apt_get install linux-image-extra-$(uname -r) linux-image-extra-virtual
@@ -75,7 +76,11 @@ function install_docker {
             ${dist_version} \
             stable"
         REPOS_UPDATED=False apt_get_update
-        apt_get install docker-ce
+        if [ -n "${UBUNTU_DOCKER_VERSION}" ]; then
+            apt_get install docker-ce=$UBUNTU_DOCKER_VERSION
+        else
+            apt_get install docker-ce
+        fi
     elif is_fedora; then
         if [[ "$lsb_dist" = "centos" ]]; then
             sudo yum-config-manager \

devstack/settings

@@ -14,6 +14,8 @@ CRIO_ALLOW_ICMP=${CRIO_ALLOW_ICMP:-true}
 CNI_CONF_DIR=${CNI_CONF_DIR:-}
 CNI_PLUGIN_DIR=${CNI_PLUGIN_DIR:-}
 
+UBUNTU_DOCKER_VERSION=${UBUNTU_DOCKER_VERSION:-}
+
 # Enable container services
 enable_service container