Revert "Bug 10074 - Encoding problems for installer"

This reverts commit d0c6e09429.

Rolling back bug 6554 work until we have more comprehensive tests.

installer/InstallAuth.pm

@@ -394,8 +394,11 @@ sub checkauth {
         -HttpOnly => 1,
         -expires => ''
     );
-
-    output_html_with_http_headers $query, $cookie, $template->output;
+    print $query->header(
+        -type    => 'text/html; charset=utf-8',
+        -cookie  => $cookie
+      ),
+      $template->output;
     exit;
 }