[mysql] prefer strings.Contains to strings.Index > 0 / < 0
[mysql] prefer strings.Contains to strings.Index > 0 / < 0

mackerelio/mackerel-agent-plugins,hiroakis/mackerel-agent-plugins,mackerelio/mackerel-agent-plugins,xorphitus/mackerel-agent-plugins,hiroakis/mackerel-agent-plugins,hiroakis/mackerel-agent-plugins,xorphitus/mackerel-agent-plugins,ariarijp/mackerel-agent-plugins,ariarijp/mackerel-agent-plugins,mackerelio/mackerel-agent-plugins,mackerelio/mackerel-agent-plugins,xorphitus/mackerel-agent-plugins,xorphitus/mackerel-agent-plugins,ariarijp/mackerel-agent-plugins,ariarijp/mackerel-agent-plugins,hiroakis/mackerel-agent-plugins