This fixes updating of property attributes for data elements when
attributes are already present on a dictionary element but get removed
by a subsequent redefinition of that element.

R=rossberg@chromium.org
BUG=v8:1772
TEST=test262/15.2.3.6-4-82-18

Review URL: http://codereview.chromium.org/8337017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9691 ce2b1a6d-e550-0410-aec6-3dcde31c8c00