Remove underspecified catch-all
Remove underspecified catch-all

There still exists a potential race-condition where the closing
transaction hits after the channel was already closed from outside. But
since the exception is not properly specified I opt for removing the
catch all.

tomashaber/raiden,tomashaber/raiden,hackaugusto/raiden,tomashaber/raiden,hackaugusto/raiden,tomashaber/raiden,tomashaber/raiden