Adds one method for each operation described in the api configuration

@api private
function defineMethods(svc) {
    AWS.util.each(svc.prototype.api.operations, function iterator(method) {
      if (svc.prototype[method]) return;
      svc.prototype[method] = function (params, callback) {
        return this.makeRequest(method, params, callback);
      };
    });
  }