Eliminate proto_tree_add_text from packet-icq.c

Change-Id: I2f4bcd8c4a6cf534bb5b6b5c5aa7e21075968ee3
Reviewed-on: https://code.wireshark.org/review/5696
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>