Fix another header include guard.

libwccl/ops/actions/unify.h

-#ifndef LIBWCCL_OPS_RELABEL_DELETE_H
-#define LIBWCCL_OPS_RELABEL_DELETE_H
+#ifndef LIBWCCL_OPS_ACTIONS_UNIFY_H
+#define LIBWCCL_OPS_ACTIONS_UNIFY_H
 
 #include <libwccl/ops/action.h>
 #include <libwccl/values/position.h>
@@ -69,4 +69,4 @@ private:
 
 } /* end ns Wccl */
 
-#endif // LIBWCCL_OPS_RELABEL_DELETE_H
+#endif // LIBWCCL_OPS_ACTIONS_UNIFY_H