How to use gemset version of gem instead of default version?

Question

I have set up rbenv and rbenv-gemset. I installed the Ruby and created the gemset.

Using OSX, there is the default version 1.17.2:

> gem list bundler
*** LOCAL GEMS ***
bundler (default: 1.17.2, 1.7.3)

I installed 1.7.3 with

> gem install bundler -v 1.7.3
Successfully installed bundler-1.7.3
1 gem installed

> rbenv rehash
> bundle -v
Bundler version 1.17.2

How to use 1.7.3?