tweak ps4 for readability

After staring at a bunch of logs, try to crisp up the ps4 output for
maximum readability.

This also adds PS4 to all calling scripts by having a common PS4 in
stackrc. It should make understanding when clean fails a bit more
straight forward.

Change-Id: Ia1f8dff5c1102c32c146a020a9f033c65d2c50de
diff --git a/clean.sh b/clean.sh
index c8b8223..3db4858 100755
--- a/clean.sh
+++ b/clean.sh
@@ -51,6 +51,7 @@
 source $TOP_DIR/lib/heat
 source $TOP_DIR/lib/neutron-legacy
 
+set -o xtrace
 
 # Extras Source
 # --------------