L1 Terminal Fault speculative side channel patch bundle [XSA-273,
    	CVE-2018-3620, CVE-2018-3646]
    Use of v2 grant tables may cause crash on ARM [XSA-268]
    x86: Incorrect MSR_DEBUGCTL handling lets guests enable BTS [XSA-269]
    oxenstored does not apply quota-maxentity [XSA-272]
    no longer need to set python_sitearch