ipa-kdb: Fix legacy password hashes generation

We were not searching for objectclass so the test to se if a user had the
posixAccount attribute was failing and the user was not marked as ipa_user.
This in turn caused us to not synchronize legacy hashes by not trying to store
the userPassword attribute.

Fixes: https://fedorahosted.org/freeipa/ticket/1820

daemons/ipa-kdb/ipa_kdb_principals.c

@@ -53,6 +53,7 @@ static char *std_principal_attrs[] = {
     "nsaccountlock",
     "passwordHistory",
 
+    "objectClass",
     NULL
 };