Add ca-certificates to required packages.

Using curl with https requires ca-certificates.

TrivialFix

Change-Id: Idcb78233fcc07fd3d5491e230ed78efc4f9b949f

docker/base/Dockerfile.j2

@@ -179,6 +179,7 @@ RUN apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 199369E540
     && apt-get upgrade -y \
     && apt-get dist-upgrade -y \
     && apt-get install -y --no-install-recommends \
+        ca-certificates \
         python \
         python-jinja2 \
         python-kazoo \