name-prefix-list: compare names only in operator==

NamePrefixList type is now a sorted container. The sort() method is
deleted.

The remove() method is renamed to erase(), in accordance with ndn-cxx
code style recommendations.

refs #4094

Change-Id: I2d3f2fa768a8dd9a51108f6f4064243b21fd6df8
diff --git a/src/lsa/name-lsa.hpp b/src/lsa/name-lsa.hpp
index 1705abc..5e4cfa6 100644
--- a/src/lsa/name-lsa.hpp
+++ b/src/lsa/name-lsa.hpp
@@ -78,7 +78,7 @@
   removeName(const ndn::Name& name)
   {
     m_wire.reset();
-    m_npl.remove(name);
+    m_npl.erase(name);
   }
 
   bool