added const char * constructors to AMQP::Login class

include/login.h

@@ -54,6 +54,14 @@ public:
     Login(std::string user, std::string password) :
         _user(std::move(user)), _password(std::move(password)) {}
 
+    /**
+     *  Constructor
+     *  @param  user
+     *  @param  password
+     */
+    Login(const char *user, const char *password) :
+        _user(user), _password(password) {}
+
     /**
      *  Destructor
      */