[core] Remove config data from session as it brings chicken-egg problem.

Configuration data stores PmaAbsoluteUri, which should be accessible
before initiating session. Otherwise there is no way to make
PmaAbsoluteUri work. PmaAbsoluteUri is needed at least for reverse
proxy setups, for example http webserver running behind https proxy.

bs_play_media.php

@@ -30,7 +30,7 @@
     if (isset($mediaType) && isset($bsReference))
     {
         // load PMA configuration
-        $PMA_Config = $_SESSION['PMA_Config'];
+        $PMA_Config = $GLOBALS['PMA_Config'];
 
         // if PMA configuration exists
         if (!empty($PMA_Config))