tests/sitecustomize.py

filter: add a comment so that people do not forget to update subsettable


Changeset 175c6fd8cacc moved `subsettable` from `mercurial/repoview.py` to
`mercurial/branchmap.py`. This mean that `filtertable` and `subsettable` are no
longer next to each other. So we add a comment to remind people to update both.

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