1.7.2 Multiplayer joining bug.

What I expected to happen was...:
I thought I would join the server normally.

What actually happened was...:
It came up with the error message: "Failed to login: Invalid session (Try restarting your game)

Steps to Reproduce:
1. Open Minecraft
2. Click Multiplayer
3. Try to join a server

• I'm not actually sure if it will