[translations] decreased mem requirement by 3MB on translation import

[Gabor Hojtsy]

Hi,

I would like to ask any interested parties to test my patch, which
reduces the memory requirements of a PO file import by 3MB (given that
you deal with a typical complete translation file for Drupal core). This
should be a major improvement for those on shared hosts, so that the
memory requirement is not lifted because of the locale import.

  http://drupal.org/node/47610

If testers are found and this is deemed working well, the patch will get
into 4.7.0.

Gabor