thread.c: fix indent
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47002 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
thread.c: fix indent
braces.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47002 b2dd03c8-39d4-4d8f-98ff-823fe69b080e