fsl.MotionOutliers output spec modified so out_file does not need to exist

Author: beausievers

nipype/interfaces/fsl/utils.py

@@ -2045,7 +2045,7 @@ class MotionOutliersInputSpec(FSLCommandInputSpec):
 
 
 class MotionOutliersOutputSpec(TraitedSpec):
-    out_file = File(exists=True)
+    out_file = File()
     out_metric_values = File(exists=True)
     out_metric_plot = File(exists=True)