Initialize Command::_name

(cherry picked from commit d0a769cb06)

src/libutil/args.cc

@@ -224,6 +224,7 @@ MultiCommand::MultiCommand(const Commands & commands)
         if (i == commands.end())
             throw UsageError("'%s' is not a recognised command", ss[0]);
         command = i->second();
+        command->_name = ss[0];
     }});
 }
 
@@ -246,6 +247,7 @@ void MultiCommand::printHelp(const string & programName, std::ostream & out)
     Table2 table;
     for (auto & i : commands) {
         auto command = i.second();
+        command->_name = i.first;
         auto descr = command->description();
         if (!descr.empty())
             table.push_back(std::make_pair(command->name(), descr));

src/libutil/args.hh

@@ -195,6 +195,8 @@ struct Command : virtual Args
 private:
     std::string _name;
 
+    friend class MultiCommand;
+
 public:
 
     virtual ~Command() { }