CAP_SYS_ADMIN is too broad, and ionice fits into CAP_SYS_NICE's grouping.

Retain CAP_SYS_ADMIN permission for backwards compatibility.
Signed-off-by: NKhazhismel Kumykov <khazhy@google.com>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>