RepoUpdater.prepareRepoDetailsForSaving() was broken here because the Repo
properties were being set before calling it, and then the Repo instance was
passed to it for comparison. So the comparison was always saying the value
was unchanged. In IndexV1Updater, the flow doesn't need those checks.
This also fixes the bug where added repos never had their name/description/
icon/etc show up in ManageRepos and RepoDetails.
@cde found this bug working on mirror support, thanks!
related to #35closes#1016