fix style issues

Change-Id: I4fbac59fdc87c8059cb09838a3604b811e14ff1f
diff --git a/src/name-assignment/assignment-random.hpp b/src/name-assignment/assignment-random.hpp
index 978a0b7..86f8096 100644
--- a/src/name-assignment/assignment-random.hpp
+++ b/src/name-assignment/assignment-random.hpp
@@ -35,7 +35,7 @@
   AssignmentRandom(const std::string& format = "");
 
   std::vector<PartialName>
-  assignName(const std::multimap<std::string, std::string> &params) override;
+  assignName(const std::multimap<std::string, std::string>& params) override;
 };
 
 } // namespace ndncert