hgweb: don't attempt to show hidden bookmarks (issue3774) localrepository._bookmarks is unfiltered, but hgweb gets a filtered repo. This fixes the resulting traceback on the 'bookmarks' page.

hgweb: fetch tipmost unfiltered rev thru the changelog This fixes a traceback when tip is filtered (e.g. because it's secret). See issue3783, for which this is a partial fix.