merge-recursive: Remove redundant path clearing for D/F conflicts

merge-recursive: Remove redundant path clearing for D/F conflicts

The code had several places where individual checks were done to remove
files that could be in the way of directories in D/F conflicts.  Not all
D/F conflicts could have a path cleared for them in such a manner, however,
leading to the need to create make_room_for_directories_of_df_conflicts()
as done in the previous patch.  That new function could not have been
incorporated into the code sooner, since not all relevant code paths had
been deferred to process_df_entry() yet, leading to the creation of even
more of these now-redundant path removals.

Clean out all of these extra D/F path clearing cases.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>