keystone: multiple vulnerabilities

Nathanael Burton discovered that Keystone did not properly verify disabled users. An authenticated but disabled user would continue to have access rights that were removed. (CVE-2013-0282)

Jonathan Murray discovered that Keystone would allow XML entity processing. A remote unauthenticated attacker could exploit this to cause a denial of service via resource exhaustion. Authenticated users could also use this to view arbitrary files on the Keystone server. (CVE-2013-1664, CVE-2013-1665)