update PETPVC tests

Author: bilgelm

nipype/interfaces/tests/test_auto_PETPVC.py

@@ -59,7 +59,7 @@ def test_PETPVC_inputs():
             mandatory=True,
         ),
         stop_crit=dict(
-            argstr='-a %.4f',
+            argstr='-s %.4f',
             usedefault=True,
         ),
     )