Spectator - Fix script error in ui_draw3d

[PabstMirror]

[ACE] (spectator) TRACE: 85515 respawnTemplate: _newCorpse=unit1, _oldKiller=unit1, _respawn=3, _respawnDelay=10 z\ace\addons\spectator\functions\fnc_respawnTemplate.sqf:26
[ACE] (spectator) TRACE: 85515 Params: _set=false, _force=true, _hide=true z\ace\addons\spectator\functions\fnc_setSpectator.sqf:25
[ACE] (spectator) TRACE: 85515 cam: _init=false z\ace\addons\spectator\functions\fnc_cam.sqf:20
[ACE] (spectator) TRACE: 85515 : player=unit1, _hidden=false z\ace\addons\spectator\functions\fnc_setSpectator.sqf:107
Error in expression <30625 ) then {
private _intersections = lineIntersectsSurfaces [_start, _end, _c>
  Error position: <lineIntersectsSurfaces [_start, _end, _c>
  Error Type Any, expected Object
File z\ace\addons\spectator\functions\fnc_ui_draw3D.sqf, line 18
[ACE] (spectator) TRACE: 85516 ui: _init=false z\ace\addons\spectator\functions\fnc_ui.sqf:20

FUNC(cam) sets GVAR(camFocus) = nil;
draw EH is removed a frame later in FUNC(ui) because it's delayed with
[{ !isNull MAIN_DISPLAY },{ [false] call FUNC(ui) }] call CBA_fnc_waitUntilAndExecute;

this just uses getVariable to prevent nil error

[commy2]

FUNC(cam) sets GVAR(camFocus) = nil;
Why not null?

[kymckay]

Setting to objNull would also work, it's only nil for consistency (fnc_cam and fnc_ui clean up all their respective GVARs on spectator exit).