Follow-up for
1cdbff1c844ce46f1d84d8feeed426ebfd550988.
After the commit
1cdbff1c844ce46f1d84d8feeed426ebfd550988, each entry .conf contains
redundant slash like the following:
```
$ cat xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx-5.9.8-200.fc33.x86_64.conf
title Fedora 33 (Thirty Three)
version 5.9.8-200.fc33.x86_64
machine-id xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
options root=/dev/nvme0n1p2 ro rootflags=subvol=system/fedora selinux=0 audit=0
linux //xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/5.9.8-200.fc33.x86_64/linux
initrd //xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/5.9.8-200.fc33.x86_64/initrd
```
BOOT_ROOT=${ENTRY_DIR_ABS%/$MACHINE_ID/$KERNEL_VERSION}
BOOT_MNT=$(stat -c %m $BOOT_ROOT)
-ENTRY_DIR=/${ENTRY_DIR_ABS#$BOOT_MNT}
+ENTRY_DIR=${ENTRY_DIR_ABS#$BOOT_MNT}
if [[ $COMMAND == remove ]]; then
rm -f "$BOOT_ROOT/loader/entries/$MACHINE_ID-$KERNEL_VERSION.conf"