When merging merge bases during a recursive merge we do not want to
leave any unmerged entries. Otherwise we cannot create a temporary
tree for the recursive merge to work with.
We failed to do so in case of a submodule conflict between merge
bases, causing a NULL pointer dereference in the next step of the
recursive merge.
Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
