[1.2] Mortar cooldown reset after reinstalling

[quandangv]

This allow players to fire mortars without any cooldown at all.

When a mortar is fired, players have to wait a cooldown of 30 seconds. But if a colonist reinstall the mortar nearby, the cooldown is reset and the mortar can be fired immediately.

This trick works for mini-turrets too, allow them to fire faster than their intended rate. Autocannons and Uranium slug turrets aren't affected as they can't be uninstalled, but for mods that allow reinstalling large turrets, this can be a big problem

[quandangv]

I have also uploaded a video of it: https://youtu.be/2j43Hsza9kE

[Pheanox]

I have confirmed this bug is still present in 1.3.  Thanks for the bug report!