Score for NoBlock/NoOp category doesn't get displayed for open changes
on All --> Open or My --> Changes. For such category, none of the label
flags i.e. recommended, liked, approved or rejected flags are set for
open changes.
Further, abandoned and merged change display different images for same
score e.g. If a -1 has been assigned, Abandoned change displays a "X"
whereas a Merged change displays "-1". A Merged can be rejected for a
NoBlock or NoOp category type.
Bug: Issue 2056
Change-Id: I29cfa02f4a43ef6be1cb94614ed75b979a84f7af
e88304abce