p11_child: properly check results of CERT_VerifyCertificateNow
With certificateUsageCheckAllUsages not only the return code of
CERT_VerifyCertificateNow() should be checked but also the usages for
which the certificate was verified. The usages checked here will all
involve CA signature checks and OCSP checks if OCSP is enabled.
Related to https://pagure.io/SSSD/sssd/issue/3560
Reviewed-by: Fabiano FidĂȘncio <fidencio@redhat.com>