Fix crud delete error message

[psergee]

Fix minor issue in CRUD delete message format:

- null
- line: 123
  class_name: DeleteError
  err: 'Failed to call delete on storage-side: %s'
  file: '...rtridge_app/myapp/.rocks/share/tarantool/crud/delete.lua'
  str: 'DeleteError: Failed to call delete on storage-side: %s'

After the fix:

- null
- line: 123
  class_name: DeleteError
  err: "Failed to call delete on storage-side: CallError: Failed for 50b73728-f3e5-4363-bfaa-011beef0d20c:
    Function returned an error: NotInitialized: crud isn't initialized on replicaset:
. . .