Add s3auth-hosts/s3auth-domainStats.h2.db to .gitignores

[carlosmiranda]

In our latest master, we have a file s3auth-hosts/s3auth-domainStats.h2.db: https://github.com/yegor256/s3auth/blob/master/s3auth-hosts/s3auth-domainStats.h2.db.

This file is actually generated by H2StatsData as a temporary storage for domain metrics, before uploading to Amazon CloudWatch. It was probably created by a unit test execution, and committed by mistake.

Let's add it to .gitignores and remove it from master.

[davvd]

I'll find a developer for the task soon...

[davvd]

thanks for the ticket, your account was topped for 15 mins, payment 40993248

[yegor256]

@carlosmiranda it's fixed, please check

[carlosmiranda]

Looks good, thanks!