Fix #110: Price column is removed when the setting is disabled.

Enable deck pricing and get the prices for a deck.

![begin](https://cloud.githubusercontent.com/assets/454057/3712702/dca5c262-152b-11e4-9f6d-400d70458714.png)

Disable deck pricing. Under the old version, the last column would remain:

![broken](https://cloud.githubusercontent.com/assets/454057/3712703/e966e152-152b-11e4-87ea-3df3e0f065bd.png)

Now it doesn't:

![fixed](https://cloud.githubusercontent.com/assets/454057/3712704/ee83e75c-152b-11e4-8f25-731c46b8d2e7.png)