eal: ignore IPC messages until init is complete

eal: ignore IPC messages until init is complete

If we receive messages that don't have a callback registered for
them, and we haven't finished initialization yet, it can be reasonably
inferred that we shouldn't have gotten the message in the first
place. Therefore, send requester a special message telling them to
ignore response to this request, as if this process wasn't there.

Since it is not possible for primary process to receive any messages
during initialization, this change in practice only applies to
secondary processes.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Jianfeng Tan <jianfeng.tan@intel.com>