Set up pre-defined policy rules automatically in devstack install

In devstack install steps, congress plugin creates policy rules
defined in CONGRESS_PREDEFINED_POLICY_FILE. It enables users to create
thier policy automatically.

Change-Id: I09a08cfd5404e0d123573c0e432dc88c126772e5
Closes-Bug: #1638742

devstack/plugin.sh

@@ -121,6 +121,15 @@ function _configure_service {
     fi
 }
 
+function create_predefined_policy {
+    if [ -n $CONGRESS_PREDEFINED_POLICY_FILE ] ; then
+        python $CONGRESS_DIR/scripts/preload-policies/output_policy_command.py \
+            $CONGRESS_PREDEFINED_POLICY_FILE | while read CONGRESS_CMD
+        do
+            $CONGRESS_CMD
+        done
+    fi
+}
 
 
 function configure_congressclient {
@@ -291,6 +300,7 @@ if is_service_enabled congress; then
         echo_summary "Starting Congress"
         start_congress_service_and_check
         configure_congress_datasources
+        create_predefined_policy
     fi
 
     if [[ "$1" == "unstack" ]]; then

devstack/settings

@@ -36,6 +36,8 @@ CONGRESS_REPLICATED=${CONGRESS_REPLICATED:-False}
 CONGRESS_TRANSPORT_URL=${CONGRESS_TRANSPORT_URL:-kombu+memory:////}
 # Mutli process deployment
 CONGRESS_MULTIPROCESS_DEPLOYMENT=${CONGRESS_MULTIPROCESS_DEPLOYMENT:-False}
+# File path to predefined policy and rules
+CONGRESS_PREDEFINED_POLICY_FILE=${CONGRESS_PREDEFINED_POLICY_FILE:-""}
 
 # Setup default directories for client
 #-------------------------------------