ssh: soft code internal channel size for testing purposes

Change-Id: I2ee0ed4ba82d2d156a7896551dea04b28cdeceb0
Reviewed-on: https://go-review.googlesource.com/35184
Run-TryBot: Han-Wen Nienhuys <hanwen@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>

ssh/mux.go

@@ -116,9 +116,9 @@ func (m *mux) Wait() error {
 func newMux(p packetConn) *mux {
 	m := &mux{
 		conn:             p,
-		incomingChannels: make(chan NewChannel, 16),
+		incomingChannels: make(chan NewChannel, chanSize),
 		globalResponses:  make(chan interface{}, 1),
-		incomingRequests: make(chan *Request, 16),
+		incomingRequests: make(chan *Request, chanSize),
 		errCond:          newCond(),
 	}
 	if debugMux {