* thread.c (rb_mutex_unlock): Mutex#unlock no longer raise
  an exception even if uses on trap. [Bug #8891]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42906 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-09-11

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42907 b2dd03c8-39d4-4d8f-98ff-823fe69b080e