Only use the externally set needs-review attribute in change-list-item

This fixes issue 11085 where a lot of changes were bolded when using
Polymer 2.

I could not find a reason why gr-change-list-item should have an
internal needsReview property and a _computeItemNeedsReview method.
In Polymer 2 an undefined change.reviewed value would result in the
needs-review attribute being added, even though gr-change-list may have
set the attribute explicitly (and correctly!) from the outside.

I have sent a question to the Polymer expert group about this, but I
think the outcome of competing computes inside and outside is undefined
at best. So the likely outcome is that we will just remove the internal
compute.

Bug: Issue 11085
Change-Id: I6d437562cb624e07454b8e32c0a051f8ef2ac182

polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item.js

@@ -40,11 +40,6 @@
         type: String,
         computed: '_computeChangeURL(change)',
       },
-      needsReview: {
-        type: Boolean,
-        reflectToAttribute: true,
-        computed: '_computeItemNeedsReview(change.reviewed)',
-      },
       statuses: {
         type: Array,
         computed: 'changeStatuses(change)',
@@ -78,10 +73,6 @@
       });
     },
 
-    _computeItemNeedsReview(reviewed) {
-      return !reviewed;
-    },
-
     _computeChangeURL(change) {
       return Gerrit.Nav.getUrlForChange(change);
     },