iscsi,nbd: do not fail in hostonly mode
systemd: do not exit the initqueue, if systemd asks a password

this prevents bailing out the initqueue, while passwords are still to be
asked
Run 'xz' and 'lzma' with multiple threads

This speeds up compression a lot on multicore systems.

https://bugzilla.redhat.com/show_bug.cgi?id=1029786

[Edited-by: Harald Hoyer: use getconf for cpu_count]