Cannot write logs to Google Logging Agent

[Naganuma Tatsumi]

Using head of master at sdhook (7a285b4) with head of master at fluent/fluent-logger-golang (fluent/fluent-logger-golang@90f0f02) cannot write any logs to Google Logging Agent due to following issues:

• AsyncConnect option was deprecated and replaced with Async, and
• MaxRetry option is -1, fluent-logger-golang never write logs.

opts.go

sh.agentClient, err = fluent.New(fluent.Config{
	AsyncConnect: true,
	MaxRetry:     -1,
})

These issues are comes from commit fluent/fluent-logger-golang#56.