We might be more clever on this and do the cleanup conditionally, but
for now this is safe solution as the checks might become stale.

This completes fix for issue #233

When we delete checks for (now) a fuzzy message, the cache needs to be
invalidated.

This might be source of issue #233.

We need this value too often, so using cache here is not optimal - it is
better to always have up to date value calculated.

This will also allow nice progress bars above translation level in future
(issue #196).

Currently translated at 100.0% (788 of 788)

This is needed to skip shortcuts like etc. which might not need shortcut
in another language.

Currently translated at 94.3% (743 of 788)

Currently translated at 20.9% (165 of 788)

Currently translated at 100.0% (788 of 788)

Currently translated at 100.0% (788 of 788)

Currently translated at 100.0% (788 of 788)

Currently translated at 100.0% (788 of 788)

Currently translated at 94.2% (742 of 788)

Currently translated at 100.0% (788 of 788)

Currently translated at 100.0% (788 of 788)

Currently translated at 100.0% (788 of 788)