MDL-22575 Preparing langconfig.php in the English pack

As all strings must be defined in the English language pack, we must add
thislanguageint into English langconfig.php, too. Also added empty
parentlang, even it is not used, for the same reason.

Backported from HEAD.

lang/en_utf8/langconfig.php

@@ -11,6 +11,7 @@ $string['locale'] = 'en_AU.UTF-8';
 $string['localewin'] = 'English_Australia.1252';
 $string['localewincharset'] = '';
 $string['oldcharset'] = 'ISO-8859-1';
+$string['parentlanguage'] = '';
 $string['strftimedate'] = '%%d %%B %%Y';
 $string['strftimedateshort'] = '%%d %%B';
 $string['strftimedatetime'] = '%%d %%B %%Y, %%I:%%M %%p';
@@ -26,6 +27,7 @@ $string['strftimetime'] = '%%I:%%M %%p';
 $string['thischarset'] = 'UTF-8';
 $string['thisdirection'] = 'ltr';
 $string['thislanguage'] = 'English';
+$string['thislanguageint'] = 'English';
 $string['thousandssep'] = ','; // thousands separator, for some languages it is '.' or ' '
 
 ?>