fix test_backup_via_unprivileged_user with ptrack enabled

It is garbage remained from old ptrack version support.

Author: funny-falcon

tests/auth_test.py

@@ -148,8 +148,6 @@ def test_backup_via_unprivileged_user(self):
         node.safe_psql(
             "test1", "create table t1 as select generate_series(0,100)")
 
-        if self.ptrack:
-            self.set_auto_conf(node, {'ptrack_enable': 'on'})
         node.stop()
         node.slow_start()