Partial revert: channel name and default output

Partial revert: channel name and default output

Since it loops on the attribute the second pass always triggered the name_set
check and directly return as an error.

commit a1dd770
Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date:   Wed Jun 15 20:26:21 2016 -0400

    Make channel read timer interval optional in session.xsd

    Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
commit c2623b8
Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date:   Wed Jun 15 20:25:48 2016 -0400

    Make channel output type optional in session.xsd

    Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>