Revert "use `df -iP` in innodb plugin on linux (care line break)"
Revert "use `df -iP` in innodb plugin on linux (care line break)"

This reverts commit fa0f862a1e1bf8b913c8263b0cd55a79b97e5c71.

ariarijp/mackerel-agent-plugins,mackerelio/mackerel-agent-plugins,hiroakis/mackerel-agent-plugins,hiroakis/mackerel-agent-plugins,mackerelio/mackerel-agent-plugins,y-kuno/mackerel-agent-plugins,ki38sato/mackerel-agent-plugins,xorphitus/mackerel-agent-plugins,y-kuno/mackerel-agent-plugins,xorphitus/mackerel-agent-plugins,hiroakis/mackerel-agent-plugins,ki38sato/mackerel-agent-plugins,ariarijp/mackerel-agent-plugins,mackerelio/mackerel-agent-plugins,ariarijp/mackerel-agent-plugins,hiroakis/mackerel-agent-plugins,ki38sato/mackerel-agent-plugins,y-kuno/mackerel-agent-plugins,xorphitus/mackerel-agent-plugins,ki38sato/mackerel-agent-plugins,mackerelio/mackerel-agent-plugins,y-kuno/mackerel-agent-plugins,ariarijp/mackerel-agent-plugins,xorphitus/mackerel-agent-plugins