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