build warning on v4.0-rc1

[Al Viro]

On Wed, Feb 25, 2015 at 11:51:43AM -0600, Felipe Balbi wrote:
> Hi Al,
> 
> commit 3b994d98a815d934ab6a77a380882865982c14f9 (get rid of the second
> argument of acct_kill()) added a new build warning when building
> kernel/acct.c. Warning can be seen below. Revert of that commit is
> non-trivial, so I haven't tried to check if reverting it fixes the
> warning.

Warning is a false positive; we really do not care about the return
value here.