Return a negative error value like the rest of the entries in this function.

Cc: <stable@vger.kernel.org>
Signed-off-by: NJoe Perches <joe@perches.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
[PM: tweaked subject line]
Signed-off-by: NPaul Moore <pmoore@redhat.com>