use UniquePtr.h from frameworks/native

Use the UniquePtr.h include from frameworks/native/include/utils
to fix the pdk build.

Change-Id: Ic415b43d2eb8c0b7ef54b6f3f75b7fa0d5f7a058
diff --git a/keystore-engine/eng_keystore.cpp b/keystore-engine/eng_keystore.cpp
index a202641..3514535 100644
--- a/keystore-engine/eng_keystore.cpp
+++ b/keystore-engine/eng_keystore.cpp
@@ -25,7 +25,7 @@
 
 #include <keystore.h>
 
-#include <UniquePtr.h>
+#include <utils/UniquePtr.h>
 
 #include <sys/socket.h>
 #include <stdarg.h>