conflict_rename_rename_1to2(): Fix checks for presence of D/F conflicts

conflict_rename_rename_1to2(): Fix checks for presence of D/F conflicts

This function is called from process_df_entry(), near the end of the merge.
Rather than just checking whether one of the sides of the merge had a
directory at the same path as one of our files, check whether that
directory is still present by this point of our merge.

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