splits sys interface into its own file

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: Ifa657dd6e5d73b6098597cd917e7da512af26641
diff --git a/test/internal_sys_mock.hpp b/test/internal_sys_mock.hpp
index 2fe0c58..55db6b7 100644
--- a/test/internal_sys_mock.hpp
+++ b/test/internal_sys_mock.hpp
@@ -2,7 +2,7 @@
 
 #include <unistd.h>
 
-#include <ipmiblob/internal/sys.hpp>
+#include <ipmiblob/internal/sys_interface.hpp>
 
 #include <gmock/gmock.h>