thread.c: no allocate before deleting

* thread.c (rb_thread_local_aset): no needs to allocate local_storage
  before deleting.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40133 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-04-06

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40134 b2dd03c8-39d4-4d8f-98ff-823fe69b080e