veyron/runtimes/google/ipc/stream/benchmark: Updated README.txt

Change-Id: I00b10eddfeabb5e8cefce811cd20525e10fc9700
diff --git a/runtimes/google/ipc/benchmark/README.txt b/runtimes/google/ipc/benchmark/README.txt
index 9230cd2..bc076c6 100644
--- a/runtimes/google/ipc/benchmark/README.txt
+++ b/runtimes/google/ipc/benchmark/README.txt
@@ -53,7 +53,7 @@
 the first RPC.
 
 $ v23 go run bmserver/main.go \
-  -veyron.tcp.address=localhost:8888 -acl='{"In":{"...":"R"}}'
+  -veyron.tcp.address=localhost:8888 -veyron.acl.literal='{"Read": {"In": ["..."]}}'
 
 (In a different shell)
 $ v23 go run bmclient/main.go \