Unable to unload UGL.

[Neitronus]

Bug Description:
Upon trying to unload UGL player gets a mag out of his weapon. Not sure if it is intented behaviour or just a bug, but i think this action should match previous changes to underbarrel weapons. E.g: If player can reload them now, he should be able to unload them too. "Fast reload" may be implemented for underbarrel weapons aswell, to match changes done to wepon system in general.

Steps to reproduce:
1. Get an M41A from marines vendor.
2. Find grenades to load your UGL, and load them into UGL, via activating weapon attachment and clicking weapon with grenades.
3. Press on a weapon with your empty hand while keeping weapon attachment active.