qemu: Build channel autosocket directory at driver startup

qemu: Build channel autosocket directory at driver startup

Rather than depend on the RPM to put it in place, since this doesn't
cover the qemu:///session case. Currently auto allocated socket path is
completely busted with qemu:///session

https://bugzilla.redhat.com/show_bug.cgi?id=1105274

And because we chown the directory at driver startup now, this also fixes
autosocket startup failures when using user/group=root

https://bugzilla.redhat.com/show_bug.cgi?id=1044561
https://bugzilla.redhat.com/show_bug.cgi?id=1146886