Packed/packing siege tries to attack sometimes

[historic_bruno]

This is not common, but I did notice it a few times in my testing. You can tell this happens if there's an error about launching a projectile without a prop point. It's likely due to a bad state transition somewhere in UnitAI.

[historic_bruno]

I believe the following errors are related:

ERROR: Unit with actor 'siege_rock_packed' launched a projectile but has no actor on 'projectile' attachpoint
ERROR: Unit with actor 'siege_rock_packed' launched a projectile but has no actor on 'projectile' attachpoint
WARNING: JavaScript warning: simulation/components/UnitAI.js line 1322
reference to undefined property this.order.data.target
WARNING: JavaScript warning: simulation/components/UnitAI.js line 1145
reference to undefined property this.order.data.target
WARNING: JavaScript warning: simulation/components/UnitAI.js line 1145
reference to undefined property this.order.data.target
WARNING: JavaScript warning: simulation/components/UnitAI.js line 1322
reference to undefined property this.order.data.target
WARNING: JavaScript warning: simulation/components/UnitAI.js line 1322
reference to undefined property this.order.data.target
WARNING: JavaScript warning: simulation/components/UnitAI.js line 1322
reference to undefined property this.order.data.target
WARNING: JavaScript warning: simulation/components/UnitAI.js line 1322
reference to undefined property this.order.data.target
WARNING: JavaScript warning: simulation/components/UnitAI.js line 2779
Script value conversion check failed: JSVAL_IS_NUMBER(v) (got type undefined)
WARNING: JavaScript warning: simulation/components/UnitAI.js line 2779
Script value conversion check failed: JSVAL_IS_NUMBER(v) (got type undefined)

[ben]

In 13318:

Fixes (un)packing siege units responding to attacks in violent stance, by ignoring attacks while (un)packing. Fixes #1751, refs #1752

[historic_bruno]

Fixed the only case of this I could find, if there are any more, please reopen with info :)