Qemu commit 767abe7 ("chardev: forbid 'wait' option with client
sockets") effectively deprecates usage of "wait" with client sockets
starting with qemu 4.0, and earlier versions ignored the value.

Cc: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>
Signed-off-by: NJán Tomko <jtomko@redhat.com>