If a file is not present on the local side, and it's unchanged between other
merge parent and ancestor, we don't use any action, neither we had a if-else
branch for that condition.
This leads to bid-merge missing that there is a such action possible which can
be performed. As test changes demonstrate, we now choose the locally deleted
side instead of choosing the remote one.
This whole logic is not acurrate as we should prompt user on what to do
when this kind of criss-cross merge is in play.