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/softkeymaster/keymaster_openssl.cpp b/softkeymaster/keymaster_openssl.cpp
index fb5b9d0..a5ba684 100644
--- a/softkeymaster/keymaster_openssl.cpp
+++ b/softkeymaster/keymaster_openssl.cpp
@@ -28,7 +28,7 @@
 #include <openssl/err.h>
 #include <openssl/x509.h>
 
-#include <UniquePtr.h>
+#include <utils/UniquePtr.h>
 
 // For debugging
 //#define LOG_NDEBUG 0