The current API allows to get votes either:
- By revision, but only the votes from a specific reviewer
- By change, but only all votes on the current patch set
Add a method that allows to get all the votes for a specific revision.
The result is returned as a multimap of the label name to a list
of approval infos for that label. The approval infos contain the Id,
name, username and email fields.
Change-Id: I35cde09b3ee059e8b03aff1c4ee2747944c3d37c
6031b05397