Look for local.json in preference to config.json.

We've had a long standing ugliness where config.json was edited by
devtest to set the ssh username, and then when one commits a
tripleo-image-elements change, it would include your username. This is
undesirable :).

Change-Id: I3129bf638e519f2b03a05cae482e26fd5aef40b1

.gitignore

@@ -9,3 +9,4 @@ dist
 build
 AUTHORS
 ChangeLog
+elements/seed-stack-config/local.json

elements/seed-stack-config/README.md

@@ -12,10 +12,12 @@ at boot-time by Heat itself).
 Usage
 -----
 
-Edit config.json to customise it for your deployment environment. The default
-is configured for nova-baremetal operation in a seed VM. The configuration
-options are documented in the actual elements that use the configuration - e.g.
-nova, neutron etc.
+Copy config.json (our basic schema) to local.json and  customise it for your
+deployment environment. The default is mostly configured for nova-baremetal
+operation in a seed VM (just add SSH key). The configuration options are
+documented in the actual elements that use the configuration - e.g.  nova,
+neutron etc. If local.json does not exist, config.json will be used, but
+this is for backwards compatability and will be removed in a future release.
 
 Configuration keys
 ------------------

elements/seed-stack-config/install.d/01-seed-stack-heat-metadata

@@ -2,4 +2,12 @@
 set -eux
 
 mkdir -p /var/lib/cloud/data
-install -D -m 0755 -o root -g root $(dirname $0)/../config.json /var/lib/heat-cfntools/cfn-init-data
+
+CONFIG_DIR="$(dirname $0)/../"
+if [ -e "$CONFIG_DIR/local.json" ]; then
+    CONFIG_FILE="$CONFIG_DIR/local.json"
+else
+    echo "Deprecated: Using config.json rather than local.json" >&2
+    CONFIG_FILE="$CONFIG_DIR/config.json"
+fi
+install -D -m 0755 -o root -g root "$CONFIG_FILE" /var/lib/heat-cfntools/cfn-init-data