Fix look of Contact Page for partner First Name

Remove the "Is a company?" option in Partner's Contact Form as these are never companies

## Vanilla
![capture d ecran de 2014-11-05 17 42 04](https://cloud.githubusercontent.com/assets/1013356/4927639/57b6ae2e-653d-11e4-8402-4a1ecd04546f.png)
![capture d ecran de 2014-11-05 17 41 52](https://cloud.githubusercontent.com/assets/1013356/4927640/59281d56-653d-11e4-8744-6e9ce0084a52.png)
## Current implementation
![capture d ecran de 2014-11-05 17 41 29](https://cloud.githubusercontent.com/assets/1013356/4927646/5fea64a0-653d-11e4-9856-19c028d1241f.png)
![capture d ecran de 2014-11-05 17 41 15](https://cloud.githubusercontent.com/assets/1013356/4927647/6125e308-653d-11e4-8c6a-ca44d9af52aa.png)
## Fixed look
![capture d ecran de 2014-11-05 17 57 31](https://cloud.githubusercontent.com/assets/1013356/4927869/33777bcc-653f-11e4-967b-746bbb86b742.png)
![capture d ecran de 2014-11-05 17 57 43](https://cloud.githubusercontent.com/assets/1013356/4927867/3245f5ee-653f-11e4-8e55-49fa5f37d0ee.png)


With your method, you have to define again all attributes of the field. It can be that across versions, these attributes change (a new onchange, groups, etc). With mine, you only overwrite desired attribute, keeping the rest unchanged.