Bug 18682 - Translatability: Get rid of [%% in translation for 2 files av-build-dropb...

Bug 18682 - Translatability: Get rid of [%% in translation for 2 files av-build-dropbox.inc

Two files av-build-dropbox.inc has linebreaks inside template directives,
 exposing internals (comments and tt code) to translations as mentioned
in initial comment.
Translators should not be confronted with such interal code.

This patch fixes it.

To test
- Verify, that code changes make sense and have no more line breaks insied
  tt directives.
- Run QA tools in newest version (checking for line breaks inside tt
  directives)
- Bonus test: Create a "language" aa-AA (perl translate create aa-AA
  from folder misc/translator, verify that lines mentioned above do
  no longer appear in aa-AA-staff-prog.po and in aa-AA-opac-bootstrap.po

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>