Fix translate script with failure function

[jaumef]

Description:

Translate script always exits after mkdocs build, even if it does not fail. Fixed by setting a function instead of an "echo && exit"

Tasks:

• [x] Replace "echo && exit" with function

[giscegit]

Documentation build URL: http://builds.gisce.net/powerp-docs/powerp_fix_translate_script/

Things to review:

• [ ] Typos in Catalan
• [ ] Typos in Spanish
• [ ] Links routes in Spanish
• [ ] Links work in Catalan
• [ ] Links work in Spanish
• [ ] Images in Spanish
• [ ] Page index shows all headers