Description of problem:
Downloading memory dump using virtctl panics.
Either using create and download of memory dump:
$ virtctl memory-dump get myvm --claim-name=memoryvolume --create-claim --output=memoryDump.dump.gz
nor downloading last associated memory dump with the vm:
$ virtctl memory-dump download myvm --output=memoryDump.dump.gz

Version-Release number of selected component (if applicable):
4.14.0, 4.13.1

How reproducible:
Always

Steps to Reproduce:
Tests Suite.[sig-storage] Memory dump Memory dump with download [test_id:9344]should create memory dump and download it

Actual results:
memory dump download fails

Expected results:
Downloading memory dump using virtctl should work