volser: Actually return errors from ListOneVolume

volser: Actually return errors from ListOneVolume

The return code from GetVolInfo was being thrown away, and success
returned to the caller, regardless of the success of this function.
As GetVolInfo's exit codes aren't suitable for sending over the wire,
just return ENODEV if this function returns failure.

(cherry picked from commit 53cc2ebaea5e5488d5285f0d13ffa47069ee986f)
Reviewed-on: http://gerrit.openafs.org/5000
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Change-Id: I72e82d014ea2320a095bb4a3281449d250a52d3b
Reviewed-on: http://gerrit.openafs.org/5006
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>