Fix failing test.

Because the EntityList constructor now accepts any iterable sequence, a
dictionary with string keys uses the key as the value to be added. Since
'a' is a valid value to construct an EmailAddress, this stopped raising
an error, thus making this test fail.

cybox/test/objects/email_message_test.py

@@ -127,7 +127,7 @@ def _compare(self, recips):
     def test_invalid_recip_type(self):
         ipv4 = Address("1.2.3.4", Address.CAT_IPV4)
         generic_address = Address("aaaa")
-        for a in [dict(a=1), 1, True, [1], ipv4, generic_address]:
+        for a in [{1: 'a'}, 1, True, [1], ipv4, generic_address]:
             self.assertRaises(ValueError, EmailRecipients, a)