message: removing unused generalisation
diff: @@ -49,8 +49,7 @@ module.exports = class Writer {
  async prepareCreate(branch, session, type, document, isSchema) {
  return withErrorHandling(document.id, type, async () => {
  await this._ensureRepo();
  - const branchName = this.branchPrefix + branch;
  - const change = await Change.create(this.repo, null, branchName, this.fetchOpts);
  + let change = await Change.create(this.repo, null, this.branchPrefix + branch, this.fetchOpts);
  let id = document.id;
  let file;
  @@ -92,8 +91,7 @@ module.exports = class Writer {
  await this._ensureRepo();
  return withErrorHandling(id, type, async () => {
  - const branchName = this.branchPrefix + branch;
  - const change = await Change.create(this.repo, document.meta.version, branchName, this.fetchOpts);
  + let change = await Change.create(this.repo, document.meta.version, this.branchPrefix + branch, this.fetchOpts);
  let file = await change.get(this._filenameFor(type, id, isSchema), { allowUpdate: true });
  let before = JSON.parse(await file.getBuffer());
  @@ -121,8 +119,7 @@ module.exports = class Writer {
  }
  await this._ensureRepo();
  return withErrorHandling(id, type, async () => {
  - const branchName = this.branchPrefix + branch;
  - const change = await Change.create(this.repo, version, branchName, this.fetchOpts);
  + let change = await Change.create(this.repo, version, this.branchPrefix + branch, this.fetchOpts);
  let file = await change.get(this._filenameFor(type, id, isSchema));
  let before = JSON.parse(await file.getBuffer());
  