packaging: delete unnecessary updating of `dirs` list

The `dirs` list is not used and it seems it also wasn't used when this
code was added in 395b0e132836 (Don't copy hidden files/directories
during `setup.py install`, 2009-07-14).

Differential Revision: https://phab.mercurial-scm.org/D8857

setup.py

@@ -1628,7 +1628,6 b' def ordinarypath(p):'
 for root in ('templates',):
     for curdir, dirs, files in os.walk(os.path.join('mercurial', root)):
         curdir = curdir.split(os.sep, 1)[1]
-        dirs[:] = filter(ordinarypath, dirs)
         for f in filter(ordinarypath, files):
             f = os.path.join(curdir, f)
             packagedata['mercurial'].append(f)