veyron2/options: Remove RuntimePrincipal opt and make PreferredProtocol
only a ClientOpt.

Also removed ROpts.

Change-Id: I746d766f9cd1c6202f847a82d80865ea9a8899db
diff --git a/runtimes/google/rt/runtime.go b/runtimes/google/rt/runtime.go
index 627fce7..f52b2d9 100644
--- a/runtimes/google/rt/runtime.go
+++ b/runtimes/google/rt/runtime.go
@@ -61,7 +61,7 @@
 	opts       []ipc.ServerOpt
 }
 
-// TODO(mattr,suharshs): Decide if ROpts would be better than this.
+// TODO(mattr,suharshs): Decide if Options would be better than this.
 func Init(ctx *context.T, appCycle veyron2.AppCycle, protocols []string, listenSpec *ipc.ListenSpec, flags flags.RuntimeFlags,
 	reservedDispatcher ipc.Dispatcher, dispatcherOpts ...ipc.ServerOpt) (*Runtime, *context.T, veyron2.Shutdown, error) {
 	r := &Runtime{deps: dependency.NewGraph()}