resolve: remove RRs from zones before an update
    
    During an update of RRs, the records of each DNS-SD service are
    replaced with new ones. However the old RRs can only be removed from
    the mDNS scopes as long as they remain accessible from the DnssdService
    structures, otherwise they remain stuck there.
    
    Therefore the removal must take place before the update.
    
    (cherry picked from commit ee3713b71ddf182852a399953968a2b39af22104)