message: session.load(): fix error handling when using callbacks
diff: @@ -112,10 +112,9 @@ export class DocumentSession extends InMemoryDocumentSessionOperations
  const objType = this.conventions.findEntityType(options.documentType);
  const loadOperation = new LoadOperation(this);
  - return this._loadInternal(ids, loadOperation)
  - .then(() => {
  - const result = BluebirdPromise.resolve(loadOperation.getDocuments<TEntity>(objType))
  - .then(docs => {
  + const result = BluebirdPromise.resolve(this._loadInternal<TEntity>(ids, loadOperation))
  + .then(() => loadOperation.getDocuments<TEntity>(objType))
  + .then((docs: EntitiesCollectionObject<TEntity> | TEntity) => {
  if (isLoadingSingle) {
  return docs[Object.keys(docs)[0]];
  }
  @@ -126,7 +125,6 @@ export class DocumentSession extends InMemoryDocumentSessionOperations
  .tapCatch(err => callback(err));
  return Promise.resolve(result);
  - });
  }
  private _loadInternal<T>(ids: string[], operation: LoadOperation): Promise<void> {
  