Change default subreaper setting

This subreaper should always be turned on for containerd unless
explicitly needed for it to be off.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

server/config.go

@@ -23,8 +23,8 @@ type Config struct {
 	Metrics MetricsConfig `toml:"metrics"`
 	// Plugins provides plugin specific configuration for the initialization of a plugin
 	Plugins map[string]toml.Primitive `toml:"plugins"`
-	// Enable containerd as a subreaper
-	Subreaper bool `toml:"subreaper"`
+	// NoSubreaper disables containerd as a subreaper
+	NoSubreaper bool `toml:"no_subreaper"`
 	// OOMScore adjust the containerd's oom score
 	OOMScore int `toml:"oom_score"`
 	// Cgroup specifies cgroup information for the containerd daemon process