Fix --deopt-every-n-times flag

(was broken since r15640)

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/19188002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15669 ce2b1a6d-e550-0410-aec6-3dcde31c8c00