Attribute access to `url` incorrectly replaced

[Bruno Alla]

Describe the bug
Issue with URL Transformer, converting an attribute access of the HttpResponseRedirectBase.url to HttpResponseRedirectBase.re_path if django.conf.urls.url is imported

To Reproduce
Consider this code (from a test case):

from django.conf.urls import url

# Define some URL patterns for tests
urlpatterns = [
    url(r'^something', Mock(), name='something'),
]

# Later: 
assert isinstance(response, HttpResponseRedirectBase)
assert response.url == expected_path

The last assertion is incorrectly converted to:

assert response.re_path == expected_path

Additional context
This is potentially affecting other rename transformers.