Connection retry counter should be reset at accessory connection

[t-yoshii]

Bug Report

Connection retry counter should be reset at accessory connection.

SDL Proxy tries to connect and increment retry counter even external accessory is not detected. This can waste the chance to retry connection after accessory is connected.

Reproduction Steps

1. Start SDL app and start SDL proxy. HU (external accessory) is not ready
2. Make app background and make it foreground again. SDL Proxy tries to connect but it fail because HU is not ready. Retry counter is incremented.
3. Repeat 2 more than 2.
4. HU connection become available.
5. SDL app detects accessory connection, however, connection is not retried because already exceeds retry counter (=3).

Expected Behavior

SDL proxy retry connection at 5.

Observed Behavior

SDL proxy does not retry at 5.

OS & Version Information

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

Test Case, Sample Code, and / or Example App

I will create PR later.