cert: fix search limit handling in cert-find
If search limits are not specified in cert-find, use the configured limits.
This applies to the certificate search in the CA as well.
Detect and report if size limit was exceeded in the certificate search in
the CA.
Do not apply limits to the internal ca-find call.
https://fedorahosted.org/freeipa/ticket/6564
Reviewed-By: Tomas Krizek <tkrizek@redhat.com>