There is no way of using system configured ca_certs in Windows

[borlaugen]

On Windows, system configured ca_certs are not picked up by urllib3 since ca_certs is set to point to certifi.where() in RESTClientObject if ssl_ca_certs is parameter is not set on InfluxDBClient.

urllib3 will use system configured ca_certs if ca_certs is set to None. It is my opinion that InfluxDBClient should mimick this behaviour as well.

Steps to reproduce:
List the minimal actions needed to reproduce the behavior.

1. Configure system defined ca_cert for a InfluxDB host
2. Create InfluxDBClient with ssl_ca_cert set to None
3. Write to api

Expected behavior:
urllib3 configures system defined ca_certs and data is written to influxdb.

Actual behavior:
An ApiException is thrown on line 238 in rest.py because of urllib3 exception:
'SSLError [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1076)'

Specifications:

• Client Version: 1.14.0
• InfluxDB Version: 2.0.4 (4e7a59b)
• Platform: Windows 10