[RFE] pesign-daemon: use an anonymous socket.

[vathpela]

It'd be good to have something like:
pesign -D --socket-name jdfljdskljf
and
pesign-client --socket-name jdfljdskljf
and have them use abstract unix sockets, so that the daemon doesn't have to rely on a bind mount of /var/run/ to work in a chroot.

[vathpela]

This will make it work better with mock+systemd-nspawn.

[chenxiaolong]

This would be great to have. Using mock + systemd-nspawn doesn't seem to work right now because /run gets mounted on top of /run/pesign (rpm-software-management/mock#140)