The uptime/ /proc/loadavg reporting in the Hurd is 1.0 for a machine without
load. This may have been caused by recent SMP work.
* gnu/services/virtualization.scm (hurd-vm-guix-extension): Set
overload-threshold to 1.8 to allow offloading to actually happen.
Change-Id: I2b5be4d8e8d884cba767702f9cdccf91717eb95d