Avoid calling b_stat() on excluded files

Case 110841: Avoid calling b_stat() on excluded files by checking
directory entries against lafe_excluded() prior to calling b_stat();
refactor the b_stat() call away from b_dir_read()
Merge branch 'case110841' of git://deathstar.dev.cpanel.net/~erin/archive-tar-builder/erins-archive-tar-builder