FIX natural search double quote

htdocs/core/lib/functions.lib.php

@@ -6276,6 +6276,8 @@ function natural_search($fields, $value, $mode=0, $nofirstand=0)
 				$i3 = 0;
 				foreach($tmpcrits as $tmpcrit)
 				{
+					if(empty($tmpcrit)) continue;
+
 					$newres .= (($i2 > 0 || $i3 > 0) ? ' OR ' : '');
 
 					if (preg_match('/\.(id|rowid)$/', $field))	// Special cas for rowid that is sometimes a ref so used as a search field