Removed unused code in AlterField.database_forwards().

from __future__ import unicode_literals

from django.db.models.fields import NOT_PROVIDED

from django.utils import six

from django.utils.functional import cached_property

from .base import Operation

            from_model = from_state.apps.get_model(app_label, self.model_name)

            from_field = from_model._meta.get_field(self.name)

            to_field = to_model._meta.get_field(self.name)

            # If the field is a relatedfield with an unresolved rel.to, just

            # set it equal to the other field side. Bandaid fix for AlterField

            # migrations that are part of a RenameModel change.

            if from_field.remote_field and from_field.remote_field.model:

                if isinstance(from_field.remote_field.model, six.string_types):

                    from_field.remote_field.model = to_field.remote_field.model

                elif to_field.remote_field and isinstance(to_field.remote_field.model, six.string_types):

                    to_field.remote_field.model = from_field.remote_field.model

            if not self.preserve_default:

                to_field.default = self.field.default

            schema_editor.alter_field(from_model, from_field, to_field)