external/scrypt: 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 external/scrypt find headers
Bug: 63762847
Change-Id: I9baf896015a1920f8a26daa2a0c549169628890f
1 file changed