vol: fix a08c3207255756c825ab69a19e04f79dd879c646

Patchset a08c3207255756c825ab69a19e04f79dd879c646 broke the suse
and windows builds by relying on C99 language syntax.  Fix it.

Reviewed-on: http://gerrit.openafs.org/6337
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
(cherry picked from commit 37a0c3d00a6e2d072faf7c2958ef0c7224add161)

Change-Id: I34963c4e941ee3d580494a87b244c67bc3806ac7
Reviewed-on: http://gerrit.openafs.org/11268
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>