bug 1490727: Align payment error page content to the centre. (#5149)
bug 1490727: Align payment error page content to the centre. (#5149)

Simply re-align the text to the centre.

**in this pr**
- https://trello.com/c/SMnw7COU/95-error-page-looks-off

Fixes this bug
![image](https://user-images.githubusercontent.com/11092019/49222427-b9767f80-f3d3-11e8-9ad5-bc0ca0b801a9.png)


SphinxKnight/kuma,jwhitlock/kuma,a2sheppy/kuma,escattone/kuma,SphinxKnight/kuma,mozilla/kuma,Elchi3/kuma,jwhitlock/kuma,SphinxKnight/kuma,a2sheppy/kuma,a2sheppy/kuma,SphinxKnight/kuma,escattone/kuma,Elchi3/kuma,jwhitlock/kuma,jwhitlock/kuma,Elchi3/kuma,a2sheppy/kuma,mozilla/kuma,mozilla/kuma,a2sheppy/kuma,escattone/kuma,mozilla/kuma,Elchi3/kuma,jwhitlock/kuma,SphinxKnight/kuma,mozilla/kuma,SphinxKnight/kuma,Elchi3/kuma