Fix usage of undeclared variables.
 * the_weekday_date() needs the global $currentday
 * ms_site_check() needs the global $current_site
 * media list table does not need to check for $total_orphans
 * upgrader has no $feedback variable, appears to be copypasta from other upgrade APIs
 * install_themes_feature_list() has no $features variable, return array() instead of a new return type of WP_Error

see #24210.



git-svn-id: http://core.svn.wordpress.org/trunk@24189 1a063a9b-81f0-0310-95a4-ce76da25c4cd