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/google_keymaster_messages_test.cpp b/google_keymaster_messages_test.cpp
index 50411b4..055cfa3 100644
--- a/google_keymaster_messages_test.cpp
+++ b/google_keymaster_messages_test.cpp
@@ -18,10 +18,11 @@
 
 #include <gtest/gtest.h>
 
+#include <keymaster/keymaster_tags.h>
+#include <keymaster/google_keymaster_utils.h>
+
 #include "google_keymaster_test_utils.h"
-#include "google_keymaster_utils.h"
 #include "google_softkeymaster.h"
-#include "keymaster_tags.h"
 
 int main(int argc, char** argv) {
     ::testing::InitGoogleTest(&argc, argv);