More robust owner membership creation

taiga/projects/models.py

@@ -754,7 +754,9 @@ def project_post_save(sender, instance, created, **kwargs):
 
     try:
         owner_role = instance.roles.get(slug=template.default_owner_role)
+    except Role.DoesNotExist:
+        owner_role = instance.roles.first()
+
+    if owner_role:
         Membership.objects.create(user=instance.owner, project=instance, role=owner_role,
                                   is_owner=True, email=instance.owner.email)
-    except Role.DoesNotExist:
-        pass