examples: edje: fix build of edje files with translation within distcheck

examples: edje: fix build of edje files with translation within distcheck

The edje text example covers the translation functionality which need the mo
and po files during edje_cc compilation. Further more the folder need to be
writable to create the new mo/po files.

We need to ensure that this is the case during a distcheck which is read only
on the source tree.