FIX #5750 Bug: CmailFile::server_parse enters an infinite loop if

$server_response is false

htdocs/core/class/CMailFile.class.php

@@ -1110,7 +1110,7 @@ class CMailFile
 			if (! ($server_response = fgets($socket, 256)) )
 			{
 				$this->error="Couldn't get mail server response codes";
-				$_retVal = false;
+				return false;
 			}
 		}