Fix stderr printing on error

Sorry about that!

Change-Id: Icef9b3dc2b6463cd5e55cde76f7f9acf8a8adb51
Release 2.1

Change-Id: I0594a1825919170d1621d028c0e72984b70bf5d8
Merge pull request #17 from muryoh/fixstderr

Fix stderr printing on error