encode() dir path has prior to computing sha1

Required for python 3 compatibility

Author: William Triplett

nipype/pipeline/engine/nodes.py

@@ -391,7 +391,7 @@ def _parameterization_dir(self, param):
             - Otherwise, return the parameterization unchanged.
         """
         if len(param) > 32:
-            return sha1(param).hexdigest()
+            return sha1(param.encode()).hexdigest()
         else:
             return param