Merge remote-tracking branch 'origin/master'

gce-properties.yml

diff --git a/gce-properties.yml b/gce-properties.yml
index 71f1199..ddd7abb 100644
--- a/gce-properties.yml
+++ b/gce-properties.yml
@@ -2,7 +2,8 @@
 credentials_file: ~/.ansible/access/default-service-account.json
 machine_type: 'n1-standard-1'
 #image: 'centos-7-v20170918'
-image: 'centos-6-v20170918'
+image: 'centos-7-v20160511'
+#image: 'centos-6-v20170918'
 zone: 'us-east1-b'
 host_prefix: 'cf'
 labels: