Change Q3TA/QL item_guard to spawn resistance buff instead of medic
In it's current config, medic is too weak to be an effective replacement for the Q3TA guard powerup.
In QL, guard powerup is updated to halve incoming damage instead of boosting health, ie it's the same as the current resistance config.
There's no resistance powerup in Q3A, Q3TA, CPMA, DeFRaG or QL, so may as well remove that compat line.