Fix incoming key conflict behaviors

Follow up to ddd2e67eb5
but for incoming messages.

* Conflict state sometimes failed to be removed even though the
  conflict was resolved.
* Messages failed to re-render after a conflict. We want to
  re-render only the error state on outgoing messages, to avoid
  flickering attachments. On incoming messages, we need to call
  render to populate the message text, avatar, etc...

// FREEBIE

js/models/messages.js

@@ -202,6 +202,7 @@
                 var promise = new textsecure.ReplayableError(error).replay();
                 if (this.isIncoming()) {
                     promise = promise.then(function(dataMessage) {
+                        this.removeConflictFor(number);
                         this.handleDataMessage(dataMessage);
                     }.bind(this));
                 } else {