e2fsck/pass2.c (check_dir_block): Check for duplicate filenames within

e2fsck/pass2.c (check_dir_block): Check for duplicate filenames within
	a single directory block (because this is the easy case;
	we don't currently check for duplicates that span
	directory blocks, for now.  Eventually for htree
	directories we can do this by searching for all directory
	blocks that have a hash overflow, and then searching the
	adjacent blocks to find all other potential duplicates.)