clfilter: `bookmark.validdest` should run on unfiltered repo The logic recently added to `bookmark.validdest` uses data about obsolete changesets to see if a bookmark destination is valid. Obsolete changesets are likely to be filtered, so we need to work on an unfiltered repository.

try:
    import coverage
    getattr(coverage, 'process_startup', lambda: None)()
except ImportError:
    pass