This can be seen via System(). In the PKI backend, if the CA is
reconfigured but not fully (e.g. an intermediate CSR is generated but no
corresponding cert set) and there are already leases (issued certs), the
CRL is unable to be built. As a result revocation fails. But in this
case we don't actually need revocation to be successful since the CRL is
useless after unmounting. By checking taint status we know if we can
simply fast-path out of revocation with a success in this case.
Fixes#946
12c00b97ef