fix whitespace in volume names

[sluetze]

the name generator implies 2 digit names. Since the "0" was missing, single-digit instances failed in creation when using lvm_backend

│ Error: error creating libvirt volume for cloudinit device tftest_init 1.iso: internal error: Child process (/sbin/lvcreate --name 'tftest_init 1.iso' -L 366K vg_raid5_backend) unexpected exit status 3:   Logical volume name "tftest_init 1.iso" is invalid.
│   Run `lvcreate --help' for more information.
│ 
│ 
│   with module.vm.libvirt_cloudinit_disk.commoninit[0],
│   on .terraform/modules/vm/storage.tf line 21, in resource "libvirt_cloudinit_disk" "commoninit":
│   21: resource "libvirt_cloudinit_disk" "commoninit" {
│ 

[MonolithProjects]

lgtm. thanks!