If there translations in the build or src dir, install them

Note: I have no idea whether the createtarball ruby script would
still add this code at the end of the top-level CMakeLists.txt
file...

Second note: to fetch the translations, run cmake with the following
option:

cmake ../krita -DKDE_L10N_AUTO_TRANSLATIONS=ON -D... This will
fetch the translations from subversion (so svn needs to be installed).
If you build master, it will fetch the right translations.

Not sure whether if you're on the stable branch, it will automatically
know that that's the stable branch...

You can also run "make fetch-translations" manually.

CCMAIL:kimageshop@kde.org
BUG:394381