Store the trusted chain in 'chain.pem'

This is useful for, e.g. OCSP stapling.

storage.go

@@ -79,6 +79,14 @@ func dumpCertsAndKey(cn string, der [][]byte, key crypto.Signer) (map[string][]b
 	}
 	m[filepath.Join(cn, "cert.pem")] = data
 
+	if len(der) > 1 {
+		data, err = encodeCerts(der[1:])
+		if err != nil {
+			return nil, err
+		}
+		m[filepath.Join(cn, "chain.pem")] = data
+	}
+
 	data, err = encodePrivateKey(key)
 	if err != nil {
 		return nil, err