Bump version in 3.13 branch.

R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/12212087

git-svn-id: https://v8.googlecode.com/svn/branches/3.13@13626 ce2b1a6d-e550-0410-aec6-3dcde31c8c00