Core should not force latest version number translations on sites

This patch fixes the problem.

I don't know why it was added, it was added to l10n_update in #1001554: Make it possible to fetch .po files for dev modules/core. Introduced in #42.
It changed (#40):

+ if (preg_match("/([0-9]+).x-dev/", $data['info']['version'], $matches)) {
...
+ }
+ // Find out if it's coming right out of HEAD
+ if (preg_match("/HEAD/", $data['info']['version'], $matches)) {
+ // Get the last available release
+ $release = array_shift($projects_info[$name]['releases']);
+ }

into (#42):
+ if (preg_match("/^[6-9].x-([0-9]+)\..*-dev$/", $data['info']['version'], $matches)) {
...
+ }
+ elseif ($name == "drupal" || preg_match("/HEAD/", $data['info']['version'], $matches)) {
+ // Pick latest available release.
+ $release = array_shift($projects_info[$name]['releases']);
+ }
I am puzzled by this change. There is hardly any description of this change:

... inability to deal with version strings generated from git_deploy module (like 7.x-3.0-rc1.16-dev) and not handling core translations.

It was removed from l10n_update in #1883154: Check version before update after the observation:

For example I am currently using Drupal version 7.17, but when I check for translation updates, there is a translation for core Drupal version 7.18.