If the last displayed dive had events, those DiveEventItems had slots connected
that would update those icons if things changed. When closing the dive log and
switching to a different one, those slots were still called and would then access
freed memory (the event structure from that old dive that is long gone by then).
This code explicitly deletes those DiveEventItems which also removes those signal
slot connections.
Fixes#3305
Sugested-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
f7e222718a