When running encrypted OSDs on multipath the expand container was
failing to find the underlying device of the encrypted block. This was
because the underlying block was located in /dev/mapper and this path
wasn't mounted in the init container "expand-encrypted-bluefs".
This will manifest like so:
```
Underlying device for crypt device ocs-deviceset-block-dev-from-san-1-data-0-5qkmm-block-dmcrypt disappeared.
```
Signed-off-by: Sébastien Han <seb@redhat.com>