Fix backup script

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/common/configs/system/backup/backup.sh

@@ -33,6 +33,7 @@ while getopts "m:b:" opt; do
 done
 
 if [ -n "$partition" ]; then
+  mkdir -p "/mnt"
   mount_location=$(mktemp -d /mnt/backup.XXXXXX)
   echo "Mounting $partition at $mount_location..."
   mount "$partition" "$mount_location"