Work-around for archive bug in SaltStack 2014.7.1

SaltStack 2014.7.1 double-quotes tar filenames which means the file can't
be found.  A workaround is not to specify tar_options, which hits a different
code path.  But that breaks the older version of SaltStack that GCE is locked
to, hence we need the version conditional (thanks @jbeda)

Fixes issue #3932

cluster/saltbase/salt/etcd/init.sls

@@ -24,7 +24,9 @@ etcd-tar:
     - source_hash: {{ etcd_tar_hash }}
     - archive_format: tar
     - if_missing: /usr/local/src/etcd-{{ etcd_version }}-linux-amd64
+{% if grains['saltversioninfo'] <= (2014, 7, 0, 0) %}
     - tar_options: xz
+{% endif %}
   file.directory:
     - name: /usr/local/src/etcd-{{ etcd_version }}-linux-amd64
     - user: root