EMP timeout interrupts magnetron effect

[drd1812]

Steps to reproduce:
1) EMP a vehicle with a short EMP duration.
2) Magnetron the EMP'd vehicle.
3) If the EMP effect ends while the vehicle is still being affected by the magnetron, the magnetron effect ends as well and the vehicle drops to the ground.

What should happen instead: The vehicle should continue to be affected by the magnetron effect, since EMP and magnetron are two seperate effects.

Tested with version 0.2p2.