Freeciv

In 3.x the terrain half of irrigate and mine became two actions of their own.

But initialize_infrastructure_cache() still files the plant and cultivate valuations under ACTIVITY_MINE and ACTIVITY_IRRIGATE, while autoworkers.c reads them back by action_id_get_activity(), i.e. ACTIVITY_PLANT and ACTIVITY_CULTIVATE, which stay at -1. So the ">= 0" test fails on every tile, in every ruleset, for AI players and human auto-workers alike.

Patch uses the right keys, and verified that this results in cultivating and planting by AI.