GSM MAP: fix detection of SMS direction when application context version is < 3

Bug: 10547
Change-Id: I4708fd9977e635c66ef1350ce5098520e4c2ce1e
Reviewed-on: https://code.wireshark.org/review/4579
Reviewed-by: Michael Mann <mmann78@netscape.net>
(cherry picked from commit 6463d2a7e66e259dabbeffbab67bcbeedd98133f)
Reviewed-on: https://code.wireshark.org/review/4775
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>