Fix: fail gracefully on --exclude on unsupported domains

Trying to use event name exclusions on unsupported domains other than
kernel (i.e. log4j, jul, and python) would hang the client. Instead,
report the error appropriately.

Fixes: #909
Signed-off-by: Antoine Busque <abusque@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>