Fix warnings and compile errors

beast/http/basic_message.h

@@ -201,7 +201,7 @@ private:
             {
                 element* const p (new element (field, value));
                 list_.push_back (*p);
-                auto const iter (set_.insert_commit (*p, d));
+                set_.insert_commit (*p, d);
                 return;
             }
             // If field already exists, append comma

beast/http/tests/basic_message.test.cpp

@@ -32,7 +32,7 @@ public:
         basic_message m;
         basic_message::parser p (m, true);
         auto result (p.write (boost::asio::buffer(text)));
-        auto result2 (p.eof());
+        p.eof();
         return std::make_pair (std::move(m), result.first);
     }