nvme/rc: fix shellcheck warning SC2086

nvme/rc: fix shellcheck warning SC2086

tests/nvme/rc:1056:7: note: Double quote to prevent globbing and word splitting. [SC2086]
tests/nvme/rc:1057:7: note: Double quote to prevent globbing and word splitting. [SC2086]

The warnings are observed with ShellCheck version 0.8.0. They are not
observed with ShellCheck version 0.9.0 and 0.10.0.

Fixes: 369d310 ("nvme: Add passthru error logging tests to nvme/039")
Signed-off-by: Yi Zhang <yi.zhang@redhat.com>
[Shin'ichiro: noted ShellCheck version dependency]
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>