disabled Korean extra functions. This is not real fix. In order to fix it

the Right-Way, all extra functions have to be rewritten. Current changes
prevent insertion of 8bit headers into new emails when Korean translation
is used. I'll submit same fix to stable if nobody stops me within 24 hours.

ChangeLog

@@ -54,6 +54,8 @@ Version 1.5.1 -- CVS
     written by Bryan Loniewski.
   - Use Special Folder Color config option works again (#931956).
   - In POP3-class, be more liberal regarding RFC-incompliant POP3-servers.
+  - Disabled Korean extra functions, because they don't provide all required 
+    options and message composition is broken.
 
 Version 1.5.0
 --------------------

functions/i18n.php

@@ -475,7 +475,8 @@ $languages['ja']['ALIAS'] = 'ja_JP';
 $languages['ko_KR']['NAME']    = 'Korean';
 $languages['ko_KR']['CHARSET'] = 'euc-KR';
 $languages['ko_KR']['LOCALE']  = 'ko_KR.EUC-KR';
-$languages['ko_KR']['XTRA_CODE'] = 'korean_charset_xtra';
+// Function does not provide all needed options
+// $languages['ko_KR']['XTRA_CODE'] = 'korean_charset_xtra';
 $languages['ko']['ALIAS'] = 'ko_KR';
 
 $languages['lt_LT']['NAME']    = 'Lithuanian';