jquery core: closes #2930. Normalizing attr() to return undefined, even when getting DOM attributes.
jquery core: closes #2930. Normalizing attr() to return undefined, even when getting DOM attributes.

git-svn-id: a6f3e0ffc78e78789c45711e92f8046af3fcb362@5683 c715fcbe-d12f-0410-84c4-316a508785bb

dantman/4query,dantman/4query