This code might be slightly slower because it performs one query per
field in the form, but I didn't notice any differences on my development
machine, and the code is now much easier to understand.
After creating a translation in spanish, it was also displaying it when selecting
the english locale.
This was due to the code picking the first translation available
With this commit, we are checking for an existing translation in the current locale
and displaying it if it exists
When visiting, for example, /admin/site_customization/information_texts?locale=fr
we were getting an `UncaughtThrowError: uncaught throw :exception`
With the following payload
```
File "/aytomad/app/participa/participacion/releases/20180726231929/app/views/admin/site_customization/information_texts/_form_field.html.erb" line 5
File "/aytomad/app/participa/participacion/releases/20180726231929/app/helpers/globalize_helper.rb" line 35 in block in globalize
```
Substituting this line seems to solve it
Note that we had to remove the portuguese local too, as it was giving a different
exception due to this change. This problem, has been solved in the original
globalization PR
