Fix bug in ITEM_NOT_UPDATABLE error check

stderr redirection to the cws-log.txt left the uploadcmd.stderr value
empty, so the ITEM_NOT_UPDATABLE error check didn't work. This is fixed
by redirecting both stderr to stdout and running tee on stdout.

Bug: twpowertools:20
Change-Id: I186036dc4e0b2717e6b8f1b44d9c3b9537761f7b
diff --git a/.zuul.yaml b/.zuul.yaml
index 56396ee..1526247 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -1,3 +1,11 @@
+# == Zuul configuration file ==
+# This file is used to configure this project and its associated jobs in Zuul.
+# Zuul is the CI/CD tool which lets us check changes before they are committed,
+# and build a canary version of the extension on a regular basis.
+# More info about Zuul:
 - job:
     name: infinitegforums-lint
     parent: web-ext-lint