Make encodings all ascii/utf-8 as appropriate.

dkim/__init__.py

@@ -430,8 +430,8 @@ def verify(message, logger=None, dnsfunc=dnstxt):
         return False
 
     # dnstxt wants Unicode
-    selector = sig[b's'].decode('latin-1')
-    domain = sig[b'd'].decode('latin-1')
+    selector = sig[b's'].decode('ascii')
+    domain = sig[b'd'].decode('ascii')
     name = "%s._domainkey.%s." % (selector, domain)
     s = dnsfunc(name).encode('utf-8')
     if not s:

dkim/tests/test_dkim.py

@@ -53,7 +53,7 @@ class TestSignAndVerify(unittest.TestCase):
 
     def dnsfunc(self, domain):
         self.assertEqual('test._domainkey.example.com.', domain)
-        return read_test_data("test.txt").decode('latin1')
+        return read_test_data("test.txt").decode('utf-8')
 
     def test_verifies(self):
         # A message verifies after being signed.