Update to 1.13.6.

This is a bug fix release.

• Improve some error messages

• Improve documentation

• Allow a principal with nonexistent policy to bypass the minimum password lifetime check, consistent with other aspects of nonexistent policies

• Fix a rare KDC denial of service vulnerability when anonymous client principals are restricted to obtaining TGTs only [CVE-2016-3120]

MFH: 2016Q3
Security: 62d45229-4fa0-11e6-9d13-206a8a720317
Security: CVE-2016-3120