We plan to write a plugin that imports a project including the review
history from another Gerrit server. In order to be able to replay
revisions in the target Gerrit server the creation timestamp and the
uploader of the revisions must be known. The revisions are retrieved
by a REST call from the source Gerrit server, hence RevisionInfo should
be extended to include the creation timestamp and the uploader.
Change-Id: I90b81ce1f3564e3becb0011ffcbb1b5ea052b64e
04cbd34e70