Memory leak in SDLLifecycleManager

[t-yoshii]

Bug Report

SDLFileManager doesn't call completion handler when it is shut down before transition to Ready state.
This causes that SDLLifecycleManager continues waiting dispatch_group. As a result, memory leaks occurs.

Reproduction Steps

1. connect SDL Proxy to HU
2. disconnect SDL Proxy during connection setup phase
3. repeat 1 - 2

Expected Behavior

Memory leak does not occur

Observed Behavior

Memory leak occurs

OS & Version Information

• iOS Version: all
• SDL iOS Version: 5.1.1, 5.2.0
• Testing Against: Our internal HU devboard

Test Case, Sample Code, and / or Example App

I will create PR later.