veyron2/ipc: Change ReflectInvoker to return an error.

Also added ReflectInvokerOrDie, which panics on all errors.

Change-Id: If9196c137e5a341e7f119d870e3a6be44a35210d
MultiPart: 1/2
diff --git a/runtimes/google/ipc/glob.go b/runtimes/google/ipc/glob.go
index 08480f0..e274f5c 100644
--- a/runtimes/google/ipc/glob.go
+++ b/runtimes/google/ipc/glob.go
@@ -23,7 +23,7 @@
 // handling for methods like Glob and Signature.
 func reservedInvoker(dispNormal, dispReserved ipc.Dispatcher) ipc.Invoker {
 	methods := &reservedMethods{dispNormal: dispNormal, dispReserved: dispReserved}
-	invoker := ipc.ReflectInvoker(methods)
+	invoker := ipc.ReflectInvokerOrDie(methods)
 	methods.selfInvoker = invoker
 	return invoker
 }
diff --git a/runtimes/google/ipc/server.go b/runtimes/google/ipc/server.go
index f4017d0..25cbdec 100644
--- a/runtimes/google/ipc/server.go
+++ b/runtimes/google/ipc/server.go
@@ -1071,7 +1071,7 @@
 	if invoker, ok := obj.(ipc.Invoker); ok {
 		return invoker
 	}
-	return ipc.ReflectInvoker(obj)
+	return ipc.ReflectInvokerOrDie(obj)
 }
 
 func (fs *flowServer) initSecurity(req *ipc.Request) old_verror.E {