MEDIUM: tools: make str2sa_range() return the FQDN even when not resolving

MEDIUM: tools: make str2sa_range() return the FQDN even when not resolving

This will be needed to later postpone server address resolution. We need the
FQDN even when it doesn't resolve. The caller then needs to check if fqdn was
set when resolve is null to detect that the address couldn't be parsed and
needs later resolution.