rt: Make the boxed region come earlier in the rust_task structure.

This is so that GC can find it more easily.

Author: pcwalton

src/rt/rust_task.cpp

@@ -23,8 +23,8 @@ rust_task::rust_task(rust_sched_loop *sched_loop, rust_task_state state,
     name(name),
     list_index(-1),
     rendezvous_ptr(0),
-    local_region(&sched_loop->local_region),
     boxed(sched_loop->kernel->env, &local_region),
+    local_region(&sched_loop->local_region),
     unwinding(false),
     cc_counter(0),
     total_stack_sz(0),

src/rt/rust_task.h

@@ -214,8 +214,8 @@ rust_task : public kernel_owned<rust_task>
     // that location before waking us up.
     uintptr_t* rendezvous_ptr;
 
-    memory_region local_region;
     boxed_region boxed;
+    memory_region local_region;
 
     // Indicates that fail() has been called and we are cleaning up.
     // We use this to suppress the "killed" flag during calls to yield.