Code style: replace tabs with spaces
diff --git a/ndn-cpp/face.hpp b/ndn-cpp/face.hpp
index fe700ef..a730161 100644
--- a/ndn-cpp/face.hpp
+++ b/ndn-cpp/face.hpp
@@ -4,7 +4,7 @@
  */
 
 #ifndef NDN_FACE_HPP
-#define	NDN_FACE_HPP
+#define NDN_FACE_HPP
 
 #include "closure.hpp"
 #include "interest.hpp"