Ruby

• st.c: get rid of VC++'s warnings of C4700 (uninitialized local
  variable used). I think that these are wrong, but should shut them
  up.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51105 b2dd03c8-39d4-4d8f-98ff-823fe69b080e