CUPS doesn't work with Kerberos in RHEL 7.6

Issue

• Following the update to Samba 4.8.3 in RHEL 7.6, Kerberos printing no longer works correctly, and instead returns an error in CUPS of "No valid device URI has been specified".
• Print jobs no longer propagate from local cupsd to central print server, reached via Samba with Kerberos based authentication. This worked before the upgrade to RHEL 7.6 from RHEL 7.5.