Clicking an already-selected branch in the sidebar should switch the log view to that revision too

Originally raised from: https://jira.atlassian.com/browse/SRCTREE-989

When the sidebar selection is already set to branch X, but you move the log view scroll position, you can't navigate back to that branch without changing the sidebar selection away from the current selection and back again. It should be possible to click again on the already-selected item to navigate back again.

Requires either changing the sidebar not to keep its selection, or tracking clicks separately to changes in selection.