Function for auth_token middleware config

Each project was configuring the auth_token middleware using several
lines of inisets. Since all the projects should configure the
auth_token middleware in the same way create a function and call it.

Change-Id: I3b6727d5a3bdc0ca600d8faa23bc6db32bb32260
diff --git a/lib/nova b/lib/nova
index 0fed00d..2a3aae1 100644
--- a/lib/nova
+++ b/lib/nova
@@ -438,17 +438,9 @@
             iniset $NOVA_CONF DEFAULT osapi_compute_listen_port "$NOVA_SERVICE_PORT_INT"
         fi
 
-        # Add keystone authtoken configuration
-
-        iniset $NOVA_CONF keystone_authtoken identity_uri $KEYSTONE_AUTH_URI
-        iniset $NOVA_CONF keystone_authtoken admin_tenant_name $SERVICE_TENANT_NAME
-        iniset $NOVA_CONF keystone_authtoken cafile $KEYSTONE_SSL_CA
-        iniset $NOVA_CONF keystone_authtoken admin_user nova
-        iniset $NOVA_CONF keystone_authtoken admin_password $SERVICE_PASSWORD
+        configure_auth_token_middleware $NOVA_CONF nova $NOVA_AUTH_CACHE_DIR
     fi
 
-    iniset $NOVA_CONF keystone_authtoken signing_dir $NOVA_AUTH_CACHE_DIR
-
     if [ -n "$NOVA_STATE_PATH" ]; then
         iniset $NOVA_CONF DEFAULT state_path "$NOVA_STATE_PATH"
         iniset $NOVA_CONF DEFAULT lock_path "$NOVA_STATE_PATH"