Run WP_Editors::enqueue_scripts() on admin_print_footer_scripts, instead of admin_footer.

Fixes incompatibility with the customizer.

Merges [28187] to the 3.9 branch.

props feedmeastraycat.
fixes #27853.

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git-svn-id: http://core.svn.wordpress.org/branches/3.9@28033 1a063a9b-81f0-0310-95a4-ce76da25c4cd