Broken encoding while adding a torrent from file + no included files afterwards.

[vi]

Tribler version/branch+revision:

devel 6a9058e

Operating system and version:

Linux

Steps to reproduce the behavior:

1. Start Tribler Core
2. Start Tribler GUI
3. Remove old version of a torrent (without data)
4. Move away (rename) the respective directory on filesystem
5. Add torrent from file
6. Observe broken encoding in filenames. Guess anyway and mark included files.
7. Accept the download.

Expected behavior:

It begins downloading the selected files, showing initially "Downloading 0%"

Actual behavior:

The torrent is visible in "Seeding 100%" state. For all files "included: no".

Manually marking files as included again in "Files" pane (filenames encoding are OK there) makes it download them like usual, showing correct status.

P.S. So it actually internally does support all excluded files, although GUI shows it strangly.

[ichorid]

Related to #3418

[ichorid]

Merging it into #3418