Tidy logging code not using UNIMPLEMENTED.

Change-Id: I7a79c1671a6ff8b2040887133b3e0925ef9a3cfe
diff --git a/runtime/quick_exception_handler.h b/runtime/quick_exception_handler.h
index b93769c..cf1ecbf 100644
--- a/runtime/quick_exception_handler.h
+++ b/runtime/quick_exception_handler.h
@@ -40,6 +40,7 @@
 
   ~QuickExceptionHandler() {
     LOG(FATAL) << "UNREACHABLE";  // Expected to take long jump.
+    UNREACHABLE();
   }
 
   void FindCatch(const ThrowLocation& throw_location, mirror::Throwable* exception,