Updated expat packages fix security vulnerabilities

Gustavo Grieco discovered an integer overflow flaw during parsing of XML. An attacker can take advantage of this flaw to cause a denial of service against an application using the Expat library (CVE-2016-9063). Rhodri James discovered an infinite loop vulnerability within the entityValueInitProcessor() function while parsing malformed XML in an external entity. An attacker can take advantage of this flaw to cause a denial of service against an application using the Expat library (CVE-2017-9233).