Fix remote security risk, pointed out by Wolfram Kriesing

pear/DB.php

@@ -534,10 +534,12 @@ class DB
                 }
                 foreach ($opts as $opt) {
                     list($key, $value) = explode('=', $opt);
+                    if (!isset($parsed[$key])) { // don't allow params overwrite
                         $parsed[$key] = urldecode($value);
                     }
                 }
             }
+        }
 
         return $parsed;
     }