dind: get image buildable for Debian

With use of Docker-CE from upstream.

Change-Id: If1a6fe3f1654a2c06c3c3882dc56cdfc6945a17e

docker/base/Dockerfile.j2

@@ -362,6 +362,7 @@ COPY apt_preferences.{{ base_distro }} /etc/apt/preferences
     {% set remote_apt_keys = [
       'http://obs.linaro.org/ERP:/18.06/Debian_9/Release.key',
       'https://bintray.com/user/downloadSubjectPublicKey?username=bintray',
+      'https://download.docker.com/linux/debian/gpg'
     ] %}
     {% set base_apt_packages = base_apt_packages +
       ['sudo',]

docker/base/sources.list.debian

@@ -15,3 +15,6 @@ deb [arch=arm64] https://dl.bintray.com/fg2it/deb-arm64/ stretch main
 
 # elasticsearch (arch:all), logstash (arch:all), kibana (arch:amd64)
 deb [arch=amd64] https://artifacts.elastic.co/packages/5.x/apt stable main
+
+# main docker repo
+deb https://download.docker.com/linux/debian stretch stable

docker/dind/Dockerfile.j2

@@ -15,10 +15,19 @@ RUN /bin/true
 {% elif base_distro in ['debian', 'ubuntu'] %}
     {% set dind_packages = [
          'btrfs-tools',
-         'docker.io',
          'openssh-server'
     ] %}
 
+    {% if base_distro in ['debian'] %}
+        {% set dind_packages = dind_packages + [
+             'docker-ce'
+        ] %}
+    {% else %}
+        {% set dind_packages = dind_packages + [
+             'docker.io'
+        ] %}
+    {% endif %}
+
     {% if install_type == 'binary' %}
         {% set dind_packages = dind_packages + [
              'python-setuptools'