Fix boost filesystem incompatibility problem

src/db.cpp

@@ -44,10 +44,10 @@ static void EnvShutdown(bool fRemoveLogFiles)
         while (it != filesystem::directory_iterator())
         {
             const filesystem::path& p = it->path();
-#if BOOST_FILESYSTEM_VERSION == 2
-            std::string f = p.filename();
-#else
+#if BOOST_FILESYSTEM_VERSION == 3
             std::string f = p.filename().generic_string();
+#else
+            std::string f = p.filename();
 #endif
             if (f.find("log.") == 0)
                 filesystem::remove(p);