[client] Fall through dns chain for custom dns zones (#5081)

dns/dns.go

@@ -47,8 +47,8 @@ type CustomZone struct {
 	Records []SimpleRecord
 	// SearchDomainDisabled indicates whether to add match domains to a search domains list or not
 	SearchDomainDisabled bool
-	// SkipPTRProcess indicates whether a client should process PTR records from custom zones
-	SkipPTRProcess bool
+	// NonAuthoritative marks user-created zones
+	NonAuthoritative bool
 }
 
 // SimpleRecord provides a simple DNS record specification for CNAME, A and AAAA records