Fix error message about read-only symbol properties.
Fix error message about read-only symbol properties.

R=rossberg@chromium.org
BUG=v8:3441
LOG=Y

Review URL: https://codereview.chromium.org/390783003

git-svn-id: f98b9d40cb02301bc76fa9e1b46ee668158567fd@22377 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh