Ensure that archives are evicted

Based on: !364 (merged)

This workarounds a bug in patrickmn/go-cache https://github.com/patrickmn/go-cache/issues/48:

If an expired item is set, it will not be evicted. It appears that Delete() ensures that OnEvicted() is called.

According to below graphs this happens quite frequently. The data is properly recycled, but gauges are not properly updated.

https://prometheus-app.gprd.gitlab.net/graph?g0.range_input=2d&g0.expr=sum(gitlab_pages_zip_archive_entries_cached)&g0.tab=0&g1.range_input=2d&g1.expr=sum(gitlab_pages_zip_cached_archives)&g1.tab=0&g2.range_input=2d&g2.expr=sum(go_memstats_alloc_bytes%7Binstance%3D~%22web-pages-.*%22%7D)&g2.tab=0&g3.range_input=2d&g3.expr=sum(gitlab_pages_zip_opened_entries_count)&g3.tab=0&g4.range_input=2d&g4.expr=sum(gitlab_pages_zip_opened)%20by%20(state)&g4.tab=0