Bug 12061 - tmpl_process3.pl - Remove obsoleted strings/backups

Bug 12061 - tmpl_process3.pl - Remove obsoleted strings/backups

This patch modifies the update process for PO files,
removing obsoleted strings. Currently they are removed
manually as part of the standar procedure of strings update.
Also backup files (*~) need to be removed manually.

To test:
1. Update translation files for any language, ej. fi-FI
(cd misc/translation; perl translate update fi-FI)

2. Check existence of obsoleted strings
egrep "#~ msg" misc/translator/po/fi-FI-*

3. Check existence of backup files
ls misc/translator/po/fi-FI-*~

4. Reset to HEAD and clean

5. Apply the patch

6. Update again, check there are no more obsoleted
strings nor backup files

Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>