libcore: use proper nativehelper headers

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

Test: modules using libcore find headers
Bug: 63762847
Change-Id: Ic5873017bcf4d1c6e0873d7030ce56ee597b580d
diff --git a/include/ScopedIcuLocale.h b/include/ScopedIcuLocale.h
index 64186e3..851de76 100644
--- a/include/ScopedIcuLocale.h
+++ b/include/ScopedIcuLocale.h
@@ -17,8 +17,8 @@
 #ifndef SCOPED_ICU_LOCALE_H_included
 #define SCOPED_ICU_LOCALE_H_included
 
-#include "JNIHelp.h"
-#include "ScopedUtfChars.h"
+#include <nativehelper/JNIHelp.h>
+#include <nativehelper/ScopedUtfChars.h>
 #include "unicode/locid.h"
 
 class ScopedIcuLocale {