libbinder: Fix initializer order error in RpcState.cpp

Building with -Wreorder-init-list fails with an error in
RpcState.cpp when initializing a BinderNode structure.
This fixes the error by manually moving the initializers
in the right order.

Bug: None
Test: m

Change-Id: I81ca1f52ad0f6955f0a32658f8f367a3539baf06