Clean up stack.sh config

* Clean up interactive configuration
* Complete moving initialization of service-specific varialbes into the
  service lib/* files.
* Cosmetic cleanups

Change-Id: Iea14359bd224dd5533201d4c7cb1437d5382c4d1
diff --git a/stackrc b/stackrc
index 19674ed..34ccfa2 100644
--- a/stackrc
+++ b/stackrc
@@ -201,6 +201,10 @@
 VOLUME_NAME_PREFIX=${VOLUME_NAME_PREFIX:-volume-}
 INSTANCE_NAME_PREFIX=${INSTANCE_NAME_PREFIX:-instance-}
 
+# Set default port for nova-objectstore
+S3_SERVICE_PORT=${S3_SERVICE_PORT:-3333}
+
+# Common network names
 PRIVATE_NETWORK_NAME=${PRIVATE_NETWORK_NAME:-"private"}
 PUBLIC_NETWORK_NAME=${PUBLIC_NETWORK_NAME:-"nova"}