pkglists/lxc: remove GnuPG things
Since LXC 4.0.12, developers decided to remove GPG and rely on HTTPS only.
Reference: https://github.com/lxc/lxc/commit/7c70b0d14396d20748084b30bac3d89da30ed8e2
This is a patch applied from turris build's hbl branch which affects hbl and hbd branches, updater-lists's develop also affects hbl and hbd branches, so this patch can be upstreamed to updater-lists now. I will remove the patch from turris build when merging this.
Edited by Michal Vasilek