scope hei_bit_string.hpp for external use

This header will been needed by user applications.

Signed-off-by: Zane Shelley <zshelle@us.ibm.com>
Change-Id: I4eae57c63e3d314d87faed364a3c314c2300d20a
diff --git a/src/isolator/hei_isolation_node.cpp b/src/isolator/hei_isolation_node.cpp
index 98f9ca4..15bf5cf 100644
--- a/src/isolator/hei_isolation_node.cpp
+++ b/src/isolator/hei_isolation_node.cpp
@@ -1,5 +1,5 @@
+#include <hei_bit_string.hpp>
 #include <isolator/hei_isolation_node.hpp>
-#include <util/hei_bit_string.hpp>
 
 namespace libhei
 {