Fix test_hashlib regression caused by my fixing hexdigest() to return a text string instead of bytes.  (This being hex digits it *should* be a text string -- that it wasn't before was a misunderstanding on my part of the C code.)
Fix test_hashlib regression caused by my fixing hexdigest() to return
a text string instead of bytes.  (This being hex digits it *should*
be a text string -- that it wasn't before was a misunderstanding on
my part of the C code.)

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator