LINUX: afs_linux_put_link is void

LINUX: afs_linux_put_link is void

The put_link callback doesn't return a value, so declare it as such.

Reviewed-on: http://gerrit.openafs.org/3636
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 336256c7a0e7d54495a070895c9d8c2057168839)

Change-Id: I5985316ea37f572039267ea117dfeae55ea96bc0
Reviewed-on: http://gerrit.openafs.org/6271
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>