* thread_pthread.c (rb_thread_create_timer_thread): fix memory
	  leak. [ruby-dev:44904] [Bug #5688]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@34532 b2dd03c8-39d4-4d8f-98ff-823fe69b080e