Qnx: Fix for compilation error in c4717944f1c4de116e9074b7a38cd7ff29b1b16d

The QComboBox::setCurrentText() function is in Qt5 only.
Using equivalent QComboBox::setEditText() instead.

Change-Id: I5d45cc93bbfcaa7510c5192312c74f5f172f3a7d
Reviewed-by: David Kaspar <dkaspar@blackberry.com>
Reviewed-by: hjk <hjk121@nokiamail.com>