The RPC header parser doesn't recognize TLS handshake traffic, so it
will close the connection prematurely with an error. To avoid that,
shunt the transport's data_ready callback when there is a TLS
handshake in progress.

The XPRT_SOCK_IGNORE_RECV flag will be toggled by code added in a
subsequent patch.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>