Very old kernels (e.g. 3.13 from Ubuntu 14.04) don't have the nvme
directory in /sys/bus/pci/devices/$bdf/, so check for its existence
before trying to list it.
Change-Id: I1f1ca04c71de6359de2b924fb9437ad03c56523b
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/393725
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
4393f43fbe