Revert "Move error_code.h into otautil."

This reverts commit 623fe7e701.

Reason for revert: Need to address device-specific modules.

Change-Id: Ib7a4191e7f193dfff49b02d3de76dda856800251

uncrypt/uncrypt.cpp

@@ -116,7 +116,7 @@
 #include <cutils/sockets.h>
 #include <fs_mgr.h>
 
-#include "otautil/error_code.h"
+#include "error_code.h"
 
 static constexpr int WINDOW_SIZE = 5;
 static constexpr int FIBMAP_RETRY_LIMIT = 3;