FIX: update opt_params path

Co-authored-by: Mathias Goncalves <goncalves.mathias@gmail.com>

Author: mnoergaard

nipype/interfaces/freesurfer/petsurfer.py

@@ -561,7 +561,7 @@ def _list_outputs(self):
             outputs["reg_rbvpet2anat"] = os.path.join(pvcdir, "aux", "rbv2anat.lta")
             outputs["reg_anat2rbvpet"] = os.path.join(pvcdir, "aux", "anat2rbv.lta")
         if self.inputs.opt:
-            outputs["opt_params"] = os.path.join(pvcdir, "aux/opt.params.dat")
+            outputs["opt_params"] = os.path.join(pvcdir, "aux", "opt.params.dat")
 
         return outputs