aio-posix: Change CONFIG_EPOLL to CONFIG_EPOLL_CREATE1

CONFIG_EPOLL was being used to guard epoll_create1 which results
in build failures on CentOS 5.

Signed-off-by: Matthew Fortune <matthew.fortune@imgtec.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 6D39441BF12EF246A7ABCE6654B023536BB85D08@hhmail02.hh.imgtec.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
