fix UnboundLocalError: local variable 'res'

closes #10
fix UnboundlocalError when a role could not be found
fix SQL user write operations when authing via LDAP

The domain_aware value was only being set when authorizing the user
which controls keystone, but it should be set for each operation the
user does as e.g. an LDAP user can try to create a new user in the SQL
backend.

closes #12