Add wheezy docker image for use not from travis (pantsbuild#5091)

Add wheezy docker image for use not from travis

This helps to build binaries supporting older operating systems without
requiring the use of travis.

It will also slightly speed up CI, as it can cache a pre-built image for the base image.

build-support/docker/travis_ci/Dockerfile

@@ -3,14 +3,7 @@
 
 # Use the standard python-2.7 docker Debian Wheezy image for binary compatibility with old linux
 # distros.
-FROM python:2.7.13-wheezy
-
-# Ensure Pants runs under the 2.7.13 interpreter.
-ENV PANTS_PYTHON_SETUP_INTERPRETER_CONSTRAINTS="['CPython==2.7.13']"
-
-# Install various things Pants requires.
-RUN apt-get update && \
-    DEBIAN_FRONTEND=noninteractive apt-get install -y default-jdk
+FROM pantsbuild/wheezy:latest
 
 # Setup mount points for the travis ci user & workdir.
 VOLUME /travis/home

build-support/docker/wheezy/Dockerfile

@@ -0,0 +1,13 @@
+# Copyright 2017 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+# Use the standard python-2.7 docker Debian Wheezy image for binary compatibility with old linux
+# distros.
+FROM python:2.7.13-wheezy
+
+# Ensure Pants runs under the 2.7.13 interpreter.
+ENV PANTS_PYTHON_SETUP_INTERPRETER_CONSTRAINTS="['CPython==2.7.13']"
+
+# Install various things Pants requires.
+RUN apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y default-jdk