Build documentation takes very long time

This seem related to the transifex translations, doing a `mvn clean install` takes more than 5 minutes.

This is really slow, but maybe should be done in other way? If the build process is still valid, this should be improved I think.

I'm doing a change in 3.4.x and seem used the english rst files, not very clear if should be changed that files or in transifex.