veyron/examples/pipetobrowser: Update Makefile

The identity command line tool interface changed in:
https://veyron-review.googlesource.com/#/c/3310/

Change-Id: I62c610d8e7726cdec0ed2b9146c5c996f520f390
diff --git a/examples/pipetobrowser/Makefile b/examples/pipetobrowser/Makefile
index 1d3f652..1abc787 100644
--- a/examples/pipetobrowser/Makefile
+++ b/examples/pipetobrowser/Makefile
@@ -59,7 +59,7 @@
 
 # Serve
 start:
-	identity --name=veyron_p2b_identity > $(VEYRON_IDENTITY_PATH)
+	identity generate veyron_p2b_identity > $(VEYRON_IDENTITY_PATH)
 	export VEYRON_IDENTITY=$(VEYRON_IDENTITY_PATH) ; \
 	export NAMESPACE_ROOT=$(NAMESPACE_ROOT); \
 	wsprd --v=1 -alsologtostderr=true -vproxy=$(VEYRON_PROXY_ADDR) --port $(VEYRON_WSPR_PORT) & \
@@ -82,4 +82,4 @@
 	rm -f browser/index.html
 	rm -f browser/build.js
 
-.PHONY: start stop clean watch
\ No newline at end of file
+.PHONY: start stop clean watch