Fixed a test failure introduced in 55a11683f7b094ae4fd0b9fa030d18a12657ba98.

tests/admin_views/tests.py

@@ -2199,7 +2199,7 @@ class AdminSearchTest(TestCase):
         from django.contrib.admin.views.main import TO_FIELD_VAR
         response = self.client.get('/test_admin/admin/auth/user/?q=joe&%s=username' % TO_FIELD_VAR)
         self.assertContains(response, "\n1 user\n")
-        self.assertContains(response, '<input type="hidden" name="t" value="username"/>', html=True)
+        self.assertContains(response, '<input type="hidden" name="_to_field" value="username"/>', html=True)
 
     def test_exact_matches(self):
         response = self.client.get('/test_admin/admin/admin_views/recommendation/?q=bar')