FIX: Missing import in ants.registration

Author: effigies

nipype/interfaces/ants/registration.py

@@ -11,6 +11,7 @@
 from builtins import range, str
 import os
 
+from ...utils.filemanip import filename_to_list
 from ..base import TraitedSpec, File, Str, traits, InputMultiPath, isdefined
 from .base import ANTSCommand, ANTSCommandInputSpec