Remove python 2 specific line.

examples/IPython Kernel/ipython-get-history.py

@@ -35,5 +35,4 b' with dest:'
     hist = HistoryAccessor()
 
     for session, lineno, cell in hist.get_range(session=session_number, raw=raw):
-      cell = cell.encode('utf-8')  # This line is only needed on Python 2.
       dest.write(cell + '\n')