Remove OpenSSH from container images

The docker images contained OpenSSH for remote connectivity used in
debugging. This is not needed with Kubernetes, since kubectl can be used
for this purpose. This change removes OpenSSH from the base image.

Change-Id: Ib009964c93a01c45c18135193a8bd496c908e0e1
diff --git a/container-images/base/Dockerfile b/container-images/base/Dockerfile
index 576bde2..dd6d08c 100644
--- a/container-images/base/Dockerfile
+++ b/container-images/base/Dockerfile
@@ -2,8 +2,7 @@
 
 RUN apt-get update && \
     apt-get -y install \
-      git \
-      openssh-client && \
+      git && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
diff --git a/container-images/base/README.md b/container-images/base/README.md
index c409505..b8b853d 100644
--- a/container-images/base/README.md
+++ b/container-images/base/README.md
@@ -7,7 +7,6 @@
 
 * Ubuntu 18.04
 * git
-* openssh client
 * create `gerrit`-user as a non-root user to run the applications
 * `tools/validate_site.sh`: validates Gerrit site directory and ensures
  filesystem permissions for gerrit user are correct