improve trusted location detection

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)

docs/registry.go

@@ -766,7 +766,7 @@ func trustedLocation(req *http.Request) bool {
 	}
 
 	for _, trusted := range trusteds {
-		if strings.HasSuffix(hostname, trusted) {
+		if hostname == trusted || strings.HasSuffix(hostname, "."+trusted) {
 			return true
 		}
 	}