Don't capitalize error strings (staticcheck).

ox.go

@@ -58,26 +58,26 @@ func oxDecrypt(m xmpp.Chat, client *xmpp.Client, iqc chan xmpp.IQ,
 	}
 	signcrypt := doc.SelectElement("signcrypt")
 	if signcrypt == nil {
-		return "error", time.Now(), errors.New("Ox: no signcrypt element")
+		return "error", time.Now(), errors.New("ox: no signcrypt element")
 	}
 	to := signcrypt.SelectElement("to")
 	if to == nil {
-		return "error", time.Now(), errors.New("Ox: no to element")
+		return "error", time.Now(), errors.New("ox: no to element")
 	}
 	jid := to.SelectAttr("jid")
 	if jid == nil {
-		return "error", time.Now(), errors.New("Ox: no jid attribute")
+		return "error", time.Now(), errors.New("ox: no jid attribute")
 	}
 	if strings.Split(jid.Value, "/")[0] != user {
-		return "error", time.Now(), errors.New("Ox: encrypted for wrong user")
+		return "error", time.Now(), errors.New("ox: encrypted for wrong user")
 	}
 	timestamp := signcrypt.SelectElement("time")
 	if timestamp == nil {
-		return "error", time.Now(), errors.New("Ox: no time element")
+		return "error", time.Now(), errors.New("ox: no time element")
 	}
 	stamp := timestamp.SelectAttr("stamp")
 	if stamp == nil {
-		return "error", time.Now(), errors.New("Ox: no stamp attribute")
+		return "error", time.Now(), errors.New("ox: no stamp attribute")
 	}
 	msgStamp, err := time.Parse("2006-01-02T15:04:05Z0700", stamp.Value)
 	if err != nil {
@@ -85,7 +85,7 @@ func oxDecrypt(m xmpp.Chat, client *xmpp.Client, iqc chan xmpp.IQ,
 	}
 	payload := signcrypt.SelectElement("payload")
 	if payload == nil {
-		return "error", time.Now(), errors.New("Ox: no payload element")
+		return "error", time.Now(), errors.New("ox: no payload element")
 	}
 	body := payload.SelectElement("body")
 	if body == nil {
@@ -205,19 +205,19 @@ func oxPublishPubKey(jid string, client *xmpp.Client, iqc chan xmpp.IQ,
 		return err
 	}
 	if iqReply.Type != "result" {
-		return errors.New("Error while publishing public key")
+		return errors.New("error while publishing public key")
 	}
 	ownPubKeyRingFromPubsub, err := oxRecvPublicKeys(client, iqc, jid, fingerprint)
 	if err != nil {
-		return errors.New("Couldn't successfully verify public key upload")
+		return errors.New("couldn't successfully verify public key upload")
 	}
 	ownPubKeyFromPubsub := ownPubKeyRingFromPubsub.GetKeys()[0]
 	ownPubKeyFromPubsubSerialized, err := ownPubKeyFromPubsub.Serialize()
 	if err != nil {
-		return errors.New("Couldn't successfully verify public key upload")
+		return errors.New("couldn't successfully verify public key upload")
 	}
 	if pubKeyBase64 != base64.StdEncoding.EncodeToString(ownPubKeyFromPubsubSerialized) {
-		return errors.New("Couldn't successfully verify public key upload")
+		return errors.New("couldn't successfully verify public key upload")
 	}
 	root = etree.NewDocument()
 	pubsub = root.CreateElement("pubsub")
@@ -252,7 +252,7 @@ func oxPublishPubKey(jid string, client *xmpp.Client, iqc chan xmpp.IQ,
 		return err
 	}
 	if iqReply.Type != "result" {
-		return errors.New("Couldn't publish public key list")
+		return errors.New("couldn't publish public key list")
 	}
 	return nil
 }
@@ -550,7 +550,7 @@ func oxGetPublicKeyRing(client *xmpp.Client, iqc chan xmpp.IQ,
 			if !savedKeysDate.Before(newestKey) {
 				pubKeys := pubKeyReadXML.SelectElements("pubkey")
 				if pubKeys == nil {
-					return nil, errors.New("Couldn't read public keys from cache")
+					return nil, errors.New("couldn't read public keys from cache")
 				}
 				for _, r := range pubKeys {
 					keyByte, err := base64.StdEncoding.DecodeString(r.Text())