ocfs2: Replace list xattr handler operations

The list operations of the ocfs2 xattr handlers were never called
anywhere.  Remove them and directly check in ocfs2_xattr_list_entry
which attributes should be skipped over instead.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: ocfs2-devel@oss.oracle.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>