[leapp] Inplace upgrade fails with dracut shell even if multi-path is not used.

Issue

• Inplace upgrade from RHEL 7.x to RHEL 8.x will drop system in dracut shell if multipath is used for OpenStack nodes.

[  158.400446] /dev/sda2: Can't open blockdev
[FAILED] Failed to mount /sysroot.
See 'systemctl status sysroot.mount' for details.
[DEPEND] Dependency failed for Initrd Root File System.
[DEPEND] Dependency failed for Reload Configuration from the Real Root.
 :
         Mounting /sysroot...
[    3.036073] XFS (dm-2): Mounting V5 Filesystem
[    3.171671] XFS (dm-2): Ending clean mount
[  OK  ] Mounted /sysroot.

• Inplace upgrade fails if /boot is on multipath.