[chore] {base,mail}/0.0.0: lint files

Part-of: #32

Author: KangOl

src/base/0.0.0/pre-models-ir_model_relation.py

@@ -4,7 +4,7 @@
 from odoo.addons.base.maintenance.migrations import util
 
 try:
-    from odoo.addons.base.models import ir_model as _ignore  # noqa
+    from odoo.addons.base.models import ir_model as _ignore
 except ImportError:
     # version 10
     from odoo.addons.base.ir import ir_model as _ignore  # noqa

src/mail/0.0.0/pre-report-migration.py

@@ -9,9 +9,10 @@ def model_cr(f):
         return f
 
 
-from odoo.addons.base.maintenance.migrations import util
 from odoo.addons.mail.models.mail_message import Message  # noqa
 
+from odoo.addons.base.maintenance.migrations import util
+
 
 def migrate(cr, version):
     pass