Be consistent about "kilo" versus "kibi".

I'm a binary man myself, but we've mostly used decimal so far, and wider
Android is mostly decimal, so...

Change-Id: Ibef78f61176569e0023a7f43196a3969c7fe794b
diff --git a/src/thread_list.cc b/src/thread_list.cc
index 0e01c0d..6c0a592 100644
--- a/src/thread_list.cc
+++ b/src/thread_list.cc
@@ -31,7 +31,7 @@
       thread_exit_cond_("thread_exit_cond_"),
       thread_suspend_count_lock_("thread suspend count lock", kThreadSuspendCountLock),
       thread_suspend_count_cond_("thread_suspend_count_cond_") {
-  VLOG(threads) << "Default stack size: " << Runtime::Current()->GetDefaultStackSize() / KB << "KiB";
+  VLOG(threads) << "Default stack size: " << PrettySize(Runtime::Current()->GetDefaultStackSize());
 }
 
 ThreadList::~ThreadList() {