Use correct variable. see [23592]. see #21767.

git-svn-id: http://core.svn.wordpress.org/trunk@23595 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-alpha-23596.

git-svn-id: http://core.svn.wordpress.org/trunk@23596 1a063a9b-81f0-0310-95a4-ce76da25c4cd