fix: attribute resolution on models which have a property named `all`  (#1405)
fix: attribute resolution on models which have a property named `all`  (#1405)

Thanks to Henrique Chehad (@henriquechehad) for the patch

Closes #1404
celerityweb/django-haystack,celerityweb/django-haystack,sgaist/django-haystack,sgaist/django-haystack,celerityweb/django-haystack,elishowk/django-haystack,barseghyanartur/django-haystack,antonyr/django-haystack,barseghyanartur/django-haystack,antonyr/django-haystack,elishowk/django-haystack,antonyr/django-haystack,elishowk/django-haystack,barseghyanartur/django-haystack,sgaist/django-haystack