disk manage: pass full NVMe device path to smartctl

disk manage: pass full NVMe device path to smartctl

This essentially reverts commit c9bd3d2 ("fix #1123: modify NVME
device path for SMART support").

The man page for smartctl states
> Use the forms "/dev/nvme[0-9]" (broadcast namespace) or
> "/dev/nvme[0-9]n[1-9]" (specific  namespace 1-9) for NVMe devices.
so it should be fine to pass the path with the specific namespace to
smartctl.

But that text was already present in the man page of version 6.5,
which is the version the commit c9bd3d2 talks about. It might be that
it was necessary to drop the specific namespace for the version
backported from Stretch to Jessie (the bug report mentions that that
version was used[0]), but it's not quite clear.

With current versions, passing in the path with the specific namespace
did work as expected[1], even on a device with multiple namespaces set
up tested locally. In PBS, the path queried via
udev::Device::from_syspath("/sys/block/{name}") is passed to smartctl
and that also included the specific namespace on the systems I tested
with a short script.

So pass the full path to make things a little bit simpler and to avoid
potential future issues like bug #2020[2].

[0]: https://bugzilla.proxmox.com/show_bug.cgi?id=1123#c3
[1]: https://forum.proxmox.com/threads/113962/post-493185
[2]: https://bugzilla.proxmox.com/show_bug.cgi?id=2020

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>