Eliminate proto_tree_add_text from some dissectors.

Change-Id: I6f1710a093fc548c718defa9b40ab68877ede977
Reviewed-on: https://code.wireshark.org/review/3470
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Reviewed-by: Anders Broman <a.broman58@gmail.com>