Previously, when being stopped, the ‘user-file-systems’ service would
attempt to unmount / and /dev, which was bound to fail. This was
harmless, apart from a couple of lines in /var/log/messages, but it was
wrong.
* gnu/services/base.scm (file-system-shepherd-services)[user-unmount]:
Remove “/” and “/dev” from the list of file systems subject to
unmounting.
Change-Id: Ieb68fe46c114909a64d54f885c94a9d7cd61f5e0