dalvikvm.cc: use proper nativehelper headers

libnativehelper exports headers under nativehelper. These were
available before incorrectly as global headers in order to give
access to jni.h.

Test: modules using dalvikvm.cc find headers
Bug: 63762847
Change-Id: I24776efb77b7d86d3b9d2ef78bc17bffe2e02f33
diff --git a/dalvikvm/dalvikvm.cc b/dalvikvm/dalvikvm.cc
index dcb49a0..e735e2f 100644
--- a/dalvikvm/dalvikvm.cc
+++ b/dalvikvm/dalvikvm.cc
@@ -21,8 +21,8 @@
 #include <algorithm>
 #include <memory>
 
-#include "JniInvocation.h"
 #include "jni.h"
+#include "nativehelper/JniInvocation.h"
 #include "nativehelper/ScopedLocalRef.h"
 #include "nativehelper/toStringArray.h"