Fix GCC error about comma at end of enumerator list.

TBR=svenpanne@chromium.org
BUG=

Review URL: https://codereview.chromium.org/17612007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15316 ce2b1a6d-e550-0410-aec6-3dcde31c8c00