Missiles/torps aren't dumped properly when replacing certain fighter weapons

[benbot16]

Round ID:

Multiple

Testmerges:

Reproduction:

1. Put torps/missiles in a ship.
2. Install a higher-tier torp/missile launcher of the same type.
3. Missiles/torps aren't dumped out, and they aren't transferred to the new launcher.

[benbot16]

Additionally, loading a different type of weapon drops the torps/missiles fine, but loading a different type of cannon doesn't drop the cannon ammo.