Fix the scale of gc_time_percentage. The unit of the original values are in seconds.
Fix the scale of gc_time_percentage. The unit of the original values are in seconds.

References:
  http://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html
  https://docs.oracle.com/javase/8/docs/technotes/tools/unix/jstat.html

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