Switch to libkeyutils.

Bug: http://b/37991155
Test: builds+boots
Change-Id: I33a3ba0d59ffd504093dc94517815c1196e95e2b
diff --git a/Ext4Crypt.cpp b/Ext4Crypt.cpp
index 969ab0b..fe1c796 100644
--- a/Ext4Crypt.cpp
+++ b/Ext4Crypt.cpp
@@ -46,7 +46,7 @@
 
 #include <cutils/fs.h>
 #include <ext4_utils/ext4_crypt.h>
-#include <ext4_utils/key_control.h>
+#include <keyutils.h>
 
 #include <android-base/file.h>
 #include <android-base/logging.h>