quic: do not update crypto keys from workers

quic: do not update crypto keys from workers

The vnet_crypto_key_add should only be called from the main thread.
This patch works around this limitation by allocating one key per worker
and updating it on the fly everytime we need to do a crypto operation.

This solution is far from ideal, but quicly has a strong assumption that
it can use a key immediately after determining it, so making the key
creation asynchronous is not a possibility.

Signed-off-by: Aloys Augustin <aloaugus@cisco.com>
Change-Id: I19fc5814195156003c36a73bb616738ba9d828f7
Type: fix