net: Rename VLANClientState to NetClientState

net: Rename VLANClientState to NetClientState

The vlan feature is no longer part of net core.  Rename VLANClientState
to NetClientState because net clients are not explicitly associated with
a vlan at all, instead they have a peer net client to which they are
connected.

This patch is a mechanical search-and-replace except for a few
whitespace fixups where changing VLANClientState to NetClientState
misaligned whitespace.

Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Zhi Yong Wu <[email protected]>
Reviewed-by: Laszlo Ersek <[email protected]>