Fixar en bugg där man inte kunde logga in i admingränssnittet.

Symptom:

Vid inloggning visas ett felmeddelande om att webbläsaren inte accepterar
cookies, samt debugmeddelanden nedan.

Orsak:

Enligt debugmeddelanden:
 – Notice: remove_custom_image_header is deprecated since version 3.4!
   Use removec_theme_support( 'custom-header' ) instead.
   in /srv/www/scouterna/wp-includes/functions.php on line 2919
 – Warning: Cannot modify header information - headers already sent by (output
   started at /srv/www/scouterna/wp-includes/functions.php:2919) in
   /srv/www/scouterna/wp-login.php on line 293

Miljö:

Testad i Wordpress 3.7-beta1-25639
Merge branch 'fix-loginbug' of https://github.com/mrManner/Scouterna-WPTheme into mrManner-fix-loginbug