Better error message when cluster has no external connectivity

It's currently not very clear from the current error message that it is
network access from inside the cluster which failed (as opposed to
network access from the host). This commit attempts to make this more
explicit.

This is somehow related to #778

pkg/crc/machine/machine.go

@@ -322,7 +322,7 @@ func Start(startConfig StartConfig) (StartResult, error) {
 	logging.Infof("Check internal and public DNS query ...")
 
 	if queryOutput, err := dns.CheckCRCPublicDNSReachable(servicePostStartConfig); err != nil {
-		logging.Warnf("Failed public DNS query: %v : %s", err, queryOutput)
+		logging.Warnf("Failed public DNS query from the cluster: %v : %s", err, queryOutput)
 	}
 
 	// Additional steps to perform after newly created VM is up