Fix byte encoding of Grades hashes

lms/djangoapps/grades/models.py

@@ -79,7 +79,7 @@ class BlockRecordList(object):
         supported by adding a label indicated which algorithm was used, e.g.,
         "sha256$j0NDRmSPa5bfid2pAcUXaxCm2Dlh3TwayItZstwyeqQ=".
         """
-        return b64encode(sha1(self.json_value).digest())
+        return b64encode(sha1(self.json_value.encode('utf-8')).digest())
 
     @lazy
     def json_value(self):

lms/djangoapps/grades/transformer.py

@@ -93,7 +93,7 @@ class GradesTransformer(BlockStructureTransformer):
             separators=(',', ':'),  # Remove spaces from separators for more compact representation
             sort_keys=True,
         )
-        return b64encode(sha1(ordered_policy).digest())
+        return b64encode(sha1(ordered_policy.encode('utf-8')).digest())
 
     @classmethod
     def _collect_explicit_graded(cls, block_structure):