test: Fix race condition in check-storage-lvm2 testUnpartitionedSpace
test: Fix race condition in check-storage-lvm2 testUnpartitionedSpace

Creating the partition table takes some time to propagate trough udev
and udisks. Make sure that the VG creation dialog sees the partition
table on the scsi_debug device, and not just the original raw device.
Otherwise the PV initialization will overwrite the partition table
instead of creating a partition.

Closes #13779

cockpituous/cockpit,cockpit-project/cockpit,cockpituous/cockpit,mvollmer/cockpit,martinpitt/cockpit,deryni/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,mvollmer/cockpit,martinpitt/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,deryni/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,deryni/cockpit,deryni/cockpit,garrett/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,martinpitt/cockpit,garrett/cockpit,garrett/cockpit,deryni/cockpit,cockpit-project/cockpit,mvollmer/cockpit,cockpituous/cockpit,deryni/cockpit,cockpit-project/cockpit,cockpituous/cockpit,garrett/cockpit,mvollmer/cockpit,cockpituous/cockpit,martinpitt/cockpit,cockpit-project/cockpit,deryni/cockpit,moraleslazaro/cockpit,garrett/cockpit