System wide installation in usr/share

I did follow the instructions from [rvm.io](https://rvm.io/rvm/install), and my rvm got installed by default in

```
$ which rvm
/usr/share/rvm/bin/rvm
```

(instead of usr/local)

I am running on an Ubuntu instance from Amazon, this is maybe why ?

Anyway, the rvm path is not detected with the system-wide install. Might want to add this path to the list of default paths checked by your gem.