repopick: encode commit subjects in utf-8 for printing

* Fixes errors like UnicodeEncodeError: 'ascii' codec can't encode
  character u'\xb0' in position 51: ordinal not in range(128) with weird
  characters in a commit message

Change-Id: Id823a5cbff482420b65d343a8241ae3826f2cee2
1 file changed