Move systemd code into pkg

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

cgroups/systemd/apply_nosystemd.go

@@ -0,0 +1,16 @@
+// +build !linux
+
+package systemd
+
+import (
+	"fmt"
+	"github.com/dotcloud/docker/pkg/cgroups"
+)
+
+func UseSystemd() bool {
+	return false
+}
+
+func systemdApply(c *Cgroup, pid int) (cgroups.ActiveCgroup, error) {
+	return nil, fmt.Errorf("Systemd not supported")
+}