Only output message about uploading if we are uploading files

This is the same fix as #107, but on top of the split branch.

*Caveat*: I've not actually managed to run `python antfs-cli.py` due to a missing constant by the looks of it:

```
$ python antfs-cli.py
Traceback (most recent call last):
  File "antfs-cli.py", line 50, in <module>
    "monitoring_b": File.Identifier.MONITORING_B,
AttributeError: class Identifier has no attribute 'MONITORING_B'
```