client: stop using /etc/pki/nssdb
Don't put any IPA certificates to /etc/pki/nssdb - IPA itself uses
/etc/ipa/nssdb and IPA CA certificates are provided to the system using
p11-kit. Remove leftovers on upgrade.
https://fedorahosted.org/freeipa/ticket/5592
Reviewed-By: David Kupka <dkupka@redhat.com>