flake8: disable import unused in dbapi

tarantool.error values import are the part of the DBAPI requirements, so
they cannot be omitted. The same rule is used in pylint.

Part of #270

Author: DifferentialOrange

tarantool/dbapi.py

@@ -4,6 +4,7 @@
 .. _PEP-249: http://www.python.org/dev/peps/pep-0249/
 """
 # pylint: disable=fixme,unused-import
+# flake8: noqa: F401
 
 from tarantool.connection import Connection as BaseConnection
 from tarantool.error import (