Added svg for owncloud 7

The menu in owncloud 7 collaboration.png loads a large image by changing it to svg it did the following,
1. load time will be faster as it is a small file
2. look cleaner and will not display a 300px by 300px image into the navigation making it cosmetically fit in.

Tested under chrome and firefox 
![screenshot from 2014-07-17 14 08 46](https://cloud.githubusercontent.com/assets/621875/3609363/31227eb2-0d79-11e4-803d-8c60d2e3125f.png)