Remove copy-pasted comment from upload_is_user_over_quota()'s phpdoc. It came...

Remove copy-pasted comment from upload_is_user_over_quota()'s phpdoc. It came from recurse_dirsize(). see #19879.

git-svn-id: https://core.svn.wordpress.org/trunk@19747 1a063a9b-81f0-0310-95a4-ce76da25c4cd