Fix callExtension error by passing empty array instead of nil

[fank]

Summary

• Replace nil with [] in all extension calls that pass no arguments
• Add missing [] args to :TIMESTAMP: calls
• Arma 3's callExtension requires the second parameter to be an array

Problem

The following errors occurred during gameplay:

[OCAP] [EXT] ERROR when calling extension: ["",0,102,":INIT:",any]
[OCAP] [EXT] ERROR when calling extension: ["",0,102,":TIMESTAMP:",any]
Error Type Any, expected Array

Changes

• fnc_initDB.sqf: Changed :GETDIR:*, :INIT:STORAGE:, and :INIT: calls to pass [] instead of nil
• fnc_eh_fired_client.sqf: Added [] args to :TIMESTAMP: calls
• fnc_eh_fired_clientBullet.sqf: Added [] args to :TIMESTAMP: calls