Don't show jobs for non-live changes

Currently the job listing for changes in the status JSON as well
as the jobs that are checked for completion, and listed in the report
all come from a method that operates on changes, not items.
Alter it to operate on items so it can return the empty list for
non-live items.  This is safe within the queue processor because of
the previous change that explicitly checks for non-live items when
determining whether changes are complete.

Include the liveness attribute in the status JSON.

Use a grey dot for non-live items in the status screen.

Change-Id: I8907108a2f8f43c75b9cabe86e7c519790d58027
diff --git a/etc/status/public_html/jquery.zuul.js b/etc/status/public_html/jquery.zuul.js
index 5d155af..c13e48c 100644
--- a/etc/status/public_html/jquery.zuul.js
+++ b/etc/status/public_html/jquery.zuul.js
@@ -370,6 +370,11 @@
                     icon_title = 'Waiting until closer to head of queue to' +
                         ' start jobs';
                 }
+                else if (change.live !== true) {
+                    // Grey icon
+                    icon_name = 'grey.png';
+                    icon_title = 'Dependent change independently tested';
+                }
                 else if (change.failing_reasons &&
                          change.failing_reasons.length > 0) {
                     var reason = change.failing_reasons.join(', ');