A DB pool `shutdown()` must close all the connections, including those just created.
Otherwise, the `env.get_known_users` test in source:trunk/trac/tests/env.py will fail on Windows:
{{{ ... os.remove(fullname) WindowsError: [Error 32] The process cannot access the file because it is being used by another process: '...\\trac-tempenv\\db\\trac.db' }}}
Authored by: cboos 2008-06-13
Parent: [r7207]
Child: [r7209]
