In 2021035cfcee08ec4c6f9d16683db8ce400bef30 a bug was introduced:
currentTrip of MainTab was not set in trip mode. Thus, when editing
the trip notes, the notes of all selected dives were edited instead.
Set the member variable and not a local variable.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>