file-systems: Handle EIO error in 'ENOENT-safe' as well....Trying to boot GuixSD when an audio CD is in the drive will die with an
"input/output error" when trying to read the superblock from the cd
drive.
This patch catches and warns in this case rather than dying.
* gnu/build/file-systems.scm (ENOENT-safe): Handle EIO.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
