Revert "[#1032] Keep track of torrent errors over restarts"

This reverts commit 2c54c696a1bb31a107f86c72341471c76b2fb0c2.

This is not working as I intended, will hopefully commit a revised version to 1.3-stable.
Update Changelog and translation files
Update copyright year in About dialog and po files
Bump version to 1.3.8
[#2514] [GTKUI] Every torrent is displayed twice in classic mode
Update changelog and bump version to 1.3.9