* st.c (st_update): remove unnecessary assignment

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45336 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-03-15

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45337 b2dd03c8-39d4-4d8f-98ff-823fe69b080e