Don't pass around the password reset key.

Merges [29327] and [29381] to the 3.9 branch.

props mdawaffe.
fixes #29060.

Built from https://develop.svn.wordpress.org/branches/3.8@29395

git-svn-id: http://core.svn.wordpress.org/branches/3.8@29173 1a063a9b-81f0-0310-95a4-ce76da25c4cd
backport 1282f9b