faulty otr messages now generate an error

src/eu/siacs/conversations/generator/MessageGenerator.java

@@ -88,4 +88,22 @@ public class MessageGenerator {
 		}
 		return packet;
 	}
+
+	public MessagePacket generateNotAcceptable(MessagePacket origin) {
+		MessagePacket packet = generateError(origin);
+		Element error = packet.addChild("error");
+		error.setAttribute("type", "modify");
+		error.setAttribute("code", "406");
+		error.addChild("not-acceptable");
+		return packet;
+	}
+	
+	private MessagePacket generateError(MessagePacket origin) {
+		MessagePacket packet = new MessagePacket();
+		packet.setId(origin.getId());
+		packet.setTo(origin.getFrom());
+		packet.setBody(origin.getBody());
+		packet.setType(MessagePacket.TYPE_ERROR);
+		return packet;
+	}
 }

src/eu/siacs/conversations/parser/MessageParser.java

@@ -92,9 +92,9 @@ public class MessageParser extends AbstractParser {
 		} catch (Exception e) {
 			String receivedId = packet.getId();
 			if (receivedId!=null) {
-				mXmppConnectionService.replyWithError(account,packet);
+				mXmppConnectionService.replyWithNotAcceptable(account,packet);
 			}
-			conversation.resetOtrSession();
+			conversation.endOtrIfNeeded();
 			return null;
 		}
 	}

src/eu/siacs/conversations/services/XmppConnectionService.java

@@ -1475,8 +1475,10 @@ public class XmppConnectionService extends Service {
 		return this.pm;
 	}
 
-	public void replyWithError(Account account, MessagePacket packet) {
-		// TODO Auto-generated method stub
-		
+	public void replyWithNotAcceptable(Account account, MessagePacket packet) {
+		if (account.getStatus() == Account.STATUS_ONLINE) {
+			MessagePacket error = this.mMessageGenerator.generateNotAcceptable(packet);
+			account.getXmppConnection().sendMessagePacket(error);
+		}
 	}
 }