libbinder: RPC more nodiscard w/ fix

Another forgotten error.

Bug: 167966510
Test: binderRpcTest
Change-Id: I48adcf428c8ce68fdc5b49d7a0314d043e78e76d
diff --git a/libs/binder/RpcSession.cpp b/libs/binder/RpcSession.cpp
index 137411b..53c9b78 100644
--- a/libs/binder/RpcSession.cpp
+++ b/libs/binder/RpcSession.cpp
@@ -688,7 +688,8 @@
 
     status_t status = OK;
     if (init) {
-        mRpcBinderState->sendConnectionInit(connection, sp<RpcSession>::fromExisting(this));
+        status =
+                mRpcBinderState->sendConnectionInit(connection, sp<RpcSession>::fromExisting(this));
     }
 
     {