While not something that many will use, editing a dive on
Subsurface-mobile should not result in data loss.
This makes the divemaster field behave in the same way as the buddy
field with regards to multiple entries.
Fixes#1853
Signed-off-by: Joakim Bygdell <j.bygdell@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>