trust-fetch-domains: create ranges for new child domains
When trust is added, we do create ranges for discovered child domains.
However, this functionality was not available through
'trust-fetch-domains' command.
Additionally, make sure non-existing trust will report proper error in
trust-fetch-domains.
https://fedorahosted.org/freeipa/ticket/4111https://fedorahosted.org/freeipa/ticket/4104