This causes garbage collection problems, as BaseConnection instances also
hold a reference to HandlerSwitcher instance. It is unclear why it fails,
as microbenchs show this should not be a problem for gc.
Also, move loggers out of HandlerSwitcher.setHandler to avoid passing a
connection parameter just for them.

git-svn-id: https://svn.erp5.org/repos/neo/trunk@2222 71dcc9de-d417-0410-9af5-da40c76e7ee4