Inclusion guard fix

Change-Id: Idf6245bb76c86817e332aca4393c9db86a1e2059
diff --git a/internal/ceres/split.h b/internal/ceres/split.h
index ec579e9..4df48c3 100644
--- a/internal/ceres/split.h
+++ b/internal/ceres/split.h
@@ -2,7 +2,7 @@
 // Author: keir@google.com (Keir Mierle)
 
 #ifndef CERES_INTERNAL_SPLIT_H_
-#define VISION_OPTIMIZATION_LEAST_SQUARES_INTERNAL_SPLIT_H_
+#define CERES_INTERNAL_SPLIT_H_
 
 #include <string>
 #include <vector>