STY: Drop unused identity branch

Author: effigies

nipype/interfaces/ants/resampling.py

@@ -502,8 +502,6 @@ def _format_arg(self, opt, spec, val):
         if opt == "output_image":
             return self._get_output_warped_filename()
         elif opt == "transforms":
-            if val == "identity":
-                return "-t identity"
             return self._get_transform_filenames()
         elif opt == "interpolation":
             if self.inputs.interpolation in [