[Bug]: format retry log

[XuanYang-cn]

Is there an existing issue for this?

• [X] I have searched the existing issues

Describe the bug

[2022-09-26T03:01:48.496Z] [2022-09-26 03:01:04 - WARNING - pymilvus.decorators]: [list_collections] retry:4, cost: 0.27s, reason: <_MultiThreadedRendezvous: StatusCode.UNAVAILABLE, failed to connect to all addresses; last error: UNKNOWN: Failed to connect to remote host: Connection refused> (decorators.py:74)

[2022-09-26T03:01:48.496Z] [2022-09-26 03:01:05 - WARNING - pymilvus.decorators]: [list_collections] retry:5, cost: 0.81s, reason: <_MultiThreadedRendezvous: StatusCode.UNAVAILABLE, failed to connect to all addresses; last error: UNKNOWN: Failed to connect to remote host: Connection refused> (decorators.py:74)

[2022-09-26T03:01:48.496Z] [2022-09-26 03:01:06 - WARNING - pymilvus.decorators]: [list_collections] retry:6, cost: 2.43s, reason: <_MultiThreadedRendezvous: StatusCode.UNAVAILABLE, failed to connect to all addresses; last error: UNKNOWN: Failed to connect to remote host: Connection refused> (decorators.py:74)

[2022-09-26T03:01:48.496Z] [2022-09-26 03:01:08 - WARNING - pymilvus.decorators]: [list_collections] retry:7, cost: 7.290000000000001s, reason: <_MultiThreadedRendezvous: StatusCode.UNAVAILABLE, failed to connect to all addresses; last error: UNKNOWN: Failed to connect to remote host: Connection refused> (decorators.py:74)

[2022-09-26T03:01:48.496Z] [2022-09-26 03:01:15 - WARNING - pymilvus.decorators]: [list_collections] retry:8, cost: 21.870000000000005s, reason: <_MultiThreadedRendezvous: StatusCode.UNAVAILABLE, failed to connect to all addresses; last error: UNKNOWN: Failed to connect to remote host: Connection refused> (decorators.py:74)

[2022-09-26T03:01:48.496Z] [2022-09-26 03:01:37 - ERROR - pymilvus.decorators]: RPC error: [list_collections], <MilvusUnavailableException: (code=1, message=server Unavailable: Retry timeout: 20s)>, <Time:{'RPC start': '2022-09-26 03:01:04.723719', 'RPC error': '2022-09-26 03:01:37.632493'}> 

Expected Behavior

No response

Steps/Code To Reproduce behavior

No response

Environment details

- Hardware/Softward conditions (OS, CPU, GPU, Memory):
- Method of installation (Docker, or from source):
- Milvus version (v0.3.1, or v0.4.0):
- Milvus configuration (Settings you made in `server_config.yaml`):

Anything else?

No response