server: fix warnings on some platforms on incompatible pointer type

Signed-off-by: Jens Axboe <axboe@fb.com>
Silence 'io_u might be used uninitialized' warning

Signed-off-by: Jens Axboe <axboe@fb.com>
solaris: fixup new cpuset functions

Signed-off-by: Jens Axboe <axboe@fb.com>