src: Renaming class to spell out them (Adl, Nhl, Npl, Npt, Npte)

Refs: #1534

Change-Id: If4a205e8ad2419505cc796027a5c863471ef5439
diff --git a/tests/test-lsdb.cpp b/tests/test-lsdb.cpp
index efc6f4a..7511fdb 100644
--- a/tests/test-lsdb.cpp
+++ b/tests/test-lsdb.cpp
@@ -21,9 +21,9 @@
 
   NamePrefixList npl1;
 
-  string s1 = "name1";
-  string s2 = "name2";
-  string router1 = "router1/1";
+  std::string s1 = "name1";
+  std::string s2 = "name2";
+  std::string router1 = "router1/1";
 
   npl1.insert(s1);
   npl1.insert(s2);