Fix unused-variable error on release builds.

TBR=ulan@chromium.org

Review URL: https://codereview.chromium.org/466333006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23279 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
[Auto-roll] Bump up version to 3.29.13.0

TBR=machenbach@chromium.org

Review URL: https://codereview.chromium.org/495973002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23280 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/master'