Allow orphaned user to be added to org

Fixed bug where an org admin was not able to add
an orphaned user to the org, in the case where the
orphan had an ancestor role that matched one of the
roles for of the org admin.

scenario to fix -- sue is member of cred1, where cred1 is
part of org1. org1 admin cannot add sue to org1, because
the cred1 role for sue has an ancestor to org1 role. The org1
admin cannot change or attach sue to org1.

tower issue #4198 and #4197

awx/main/access.py

@@ -11,7 +11,6 @@ from functools import reduce
 from django.conf import settings
 from django.db.models import Q, Prefetch
 from django.contrib.auth.models import User
-from django.contrib.contenttypes.models import ContentType
 from django.utils.translation import ugettext_lazy as _
 from django.core.exceptions import ObjectDoesNotExist
 
@@ -650,8 +649,8 @@ class UserAccess(BaseAccess):
                 # in these cases only superusers can modify orphan users
                 return False
             return not obj.roles.all().exclude(
-                content_type=ContentType.objects.get_for_model(User)
-            ).filter(ancestors__in=self.user.roles.all()).exists()
+                ancestors__in=self.user.roles.all()
+            ).exists()
         else:
             return self.is_all_org_admin(obj)