Add a label to the second password field on User New and User Edit screen. props MikeHansenMe. fixes #20294.

git-svn-id: http://core.svn.wordpress.org/trunk@24531 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Install: Fix the value of the `for` attribute for the label of the username field.

git-svn-id: http://core.svn.wordpress.org/trunk@24532 1a063a9b-81f0-0310-95a4-ce76da25c4cd