normalize volume.target to drop trailing slash

[ndeloof]

No description provided.

[jhrotko]

So, we moved the clean path to compose-go and cleaned up from compose in order to avoid inconsistensies?

[ndeloof]

in docker/compose we ran volume.Target = path.Clean(volume.Target) within a func

1. this was buggy as caller value was left unchanged (would need to pass a pointer)
2. this is unsafe we "fix" the model inside some unrelated subfunction
   with this change, we get volume target cleaned after model is loaded, so we can safely compare values.