storage: lvm: Don't overwrite lvcreate errors

storage: lvm: Don't overwrite lvcreate errors

Before:
$ sudo virsh vol-create-as --pool vgvirt sparsetest --capacity 16M --allocation 0
error: Failed to create vol sparsetest
error: internal error Child process (/usr/sbin/lvchange -aln vgvirt/sparsetest) unexpected exit status 5:   One or more specified logical volume(s) not found.

After:
$ sudo virsh vol-create-as --pool vgvirt sparsetest --capacity 16M --allocation 0
error: Failed to create vol sparsetest
error: internal error Child process (/usr/sbin/lvcreate --name sparsetest -L 0K --virtualsize 16384K vgvirt) unexpected exit status 5:   Unable to create new logical volume with no extents