net: use Netdev instead of NetClientOptions in client init

net: use Netdev instead of NetClientOptions in client init

This way we no longer need NetClientOptions and can convert Netdev
into a flat union.

Signed-off-by: Kővágó, Zoltán <DirtY.iCE.hu@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <93ffdfed7054529635e6acb935150d95dc173a12.1441627176.git.DirtY.iCE.hu@gmail.com>

[rework net_client_init1() to pass Netdev by copying from NetdevLegacy,
rather than merging the two types - which means that we still need
NetClientOptions after all.  Rebase to qapi changes. The bulk of the
patch is mechanical, replacing 'opts' by 'netdev->opts', while
net_client_init1() takes care of converting between legacy and modern
types.]

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1468468228-27827-2-git-send-email-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>