Update dockerfiles to include ssh client

It was discovered that some base images when used as an override to
the specified default images do not include the openssh package.
This is particularly problematic if a user wishes to use ssh access
when specifying their repositories in the site's site-definition.yaml

Without the openssh package the following error occurs:
ERROR pegleg.engine.util.git:normalize_repo_path [nnn] The
repo_path=ssh://user@domain:port/site-repo is not a valid Git repo

Adding the openssh package does not impact the current base images as
they already include it, but has the added benefit of ensuring that
a non-default base image will still work with Pegleg.

Change-Id: I154c3db5071a373ad16cb0a0c4c6103b6ea8ac4e

images/pegleg/Dockerfile.opensuse_15

@@ -12,26 +12,27 @@ LABEL org.opencontainers.image.licenses='Apache-2.0'
 ENV LANG=C.UTF-8
 ENV LC_ALL=C.UTF-8
 
-RUN set -x && \
-    zypper up -y && \
-    zypper --non-interactive install \
-       git-core \
-       which \
-       gcc \
-       curl \
-       python3-devel \
-       python3-setuptools \
-       python3-dbm \
-       python3-pip && \
-       pip install --upgrade pip && \
-       zypper clean -a && \
-       rm -rf \
+RUN set -x \
+    && zypper up -y \
+    && zypper --non-interactive install \
+         curl \
+         gcc \
+         git-core \
+         openssh \
+         python3-dbm \
+         python3-devel \
+         python3-pip \
+         python3-setuptools \
+         which \
+    && python3 -m pip install -U pip \
+    && zypper clean -a \
+    && rm -rf \
          /tmp/* \
-         /var/tmp/* \
-         /var/log/* \
-         /usr/share/man \
          /usr/share/doc \
-         /usr/share/doc-base
+         /usr/share/doc-base \
+         /usr/share/man \
+         /var/log/* \
+         /var/tmp/*
 
 VOLUME /var/pegleg
 WORKDIR /var/pegleg

images/pegleg/Dockerfile.ubuntu_xenial

@@ -21,6 +21,7 @@ RUN set -ex \
          git \
          libssl-dev \
          netbase \
+         openssh-client \
          python3-dev \
          python3-pip \
          python3-setuptools \
@@ -33,6 +34,7 @@ RUN set -ex \
          /usr/share/doc-base \
          /usr/share/man \
          /var/lib/apt/lists/* \
+         /var/log/* \
          /var/tmp/*
 
 VOLUME /var/pegleg