Switch to new vendor directory layout

Fixes #113

Signed-off-by: Marcos Lilljedahl <marcosnils@gmail.com>

vendor/github.com/opencontainers/runc/libcontainer/cgroups/cgroups_test.go

@@ -0,0 +1,18 @@
+// +build linux
+
+package cgroups
+
+import (
+	"testing"
+)
+
+func TestParseCgroups(t *testing.T) {
+	cgroups, err := ParseCgroupFile("/proc/self/cgroup")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, ok := cgroups["cpu"]; !ok {
+		t.Fail()
+	}
+}