Added import DatabaseError needed to proper handling possible exception

Author: pavel-zotov

tests/functional/fkey/primary/test_insert_pk_07.py

@@ -16,7 +16,7 @@
 
 import pytest
 from firebird.qa import *
-from firebird.driver import tpb, Isolation
+from firebird.driver import tpb, Isolation, DatabaseError
 
 init_script = """
     create table master_table (

tests/functional/syspriv/test_trace_any_attachment.py

@@ -21,6 +21,7 @@
 import locale
 import re
 from firebird.qa import *
+from firebird.driver import DatabaseError
 
 db = db_factory()
 tmp_user = user_factory('db', name='tmp_syspriv_user', password='123')