Reorganize system/keymaster.

This CL moves the includes that should be exported to include/ and
removes the trusty-specific code (some of which is moving to
hardware/google and some of which is moving to the trusty tree.)

Change-Id: Ie4fabf6b5c5f36b50c2f5ff356548ca2e9140fcb
diff --git a/key_blob.cpp b/key_blob.cpp
index 0e8a640..b29b855 100644
--- a/key_blob.cpp
+++ b/key_blob.cpp
@@ -19,9 +19,10 @@
 #include <openssl/aes.h>
 #include <openssl/sha.h>
 
+#include <keymaster/google_keymaster_utils.h>
+
 #include "ae.h"
 #include "key_blob.h"
-#include "google_keymaster_utils.h"
 
 namespace keymaster {