- prevent from PHP error when iconv doesn't support //IGNORE (#1486375)

program/include/main.inc

@@ -195,7 +195,7 @@ function rcube_charset_convert($str, $from, $to=NULL)
 
   // convert charset using iconv module  
   if (function_exists('iconv') && $from != 'UTF-7' && $to != 'UTF-7') {
-    $_iconv = iconv($from, $to . '//IGNORE', $str);
+    $_iconv = @iconv($from, $to . '//IGNORE', $str);
     if ($_iconv !== false) {
         return $_iconv;
     }

program/include/rcube_shared.inc

@@ -518,7 +518,7 @@ function rc_utf8_clean($input)
   if (function_exists('mb_convert_encoding') && ($res = mb_convert_encoding($input, 'UTF-8', 'UTF-8')) !== false)
     return $res;
 
-  if (function_exists('iconv') && ($res = iconv('UTF-8', 'UTF-8//IGNORE', $input)) !== false)
+  if (function_exists('iconv') && ($res = @iconv('UTF-8', 'UTF-8//IGNORE', $input)) !== false)
     return $res;
 
   $regexp = '/^('.