Feature Request: --enforce-tableacl-config: don't exit process on reload

[wiebeytec]

Feature Description

Current behavior

When you are running a vttablet with --enforce-tableacl-config:

• It won't start with invalid config.
• It exits after issueing a SIGHUP when the config is invalid.

Requested behavior

• Unchanged: It won't start with invalid config.
• It refuses to load the new file on SIGHUP (and logs the error), but does not exit.

Use Case(s)

Preventing unnecessary outage when someone makes a config mistake.