DirectCall - prevent problems with exitWith

[PabstMirror]

Fixes #689

[commy2]

This would mean that the _x variable is overwritten.

[PabstMirror]

_x = 5; 
x3 = [{_x = 4; systemChat str _x; }, 3] call cba_fnc_directCall;
systemChat str _x;

prints 4, 5.
I think the _x is privated from the apply, not sure?

[commy2]

I think it should just be:

- _CBA_return = [_x] apply _CBA_code select 0;
+ _CBA_return = [_x] apply _CBA_code param [0];

[PabstMirror]

That would fail if something returns an array:

_code = {num = random 1; if (num < 0.5) exitWith {[true, num]}; [false, num]};

[false,0.914843]
true

[commy2]

Then I think your solution is best. But with [_x] and not [nil].