license: SPDX: update all vc files to use SPDX style

When imported, the vc files carried in the 'full style' apache
license text, but the standard for kata is to use SPDX style.
Update the relevant files to SPDX.

Fixes: #227

Signed-off-by: Graham whaley <graham.whaley@intel.com>

virtcontainers/pkg/hyperstart/hyperstart.go

@@ -1,17 +1,6 @@
-//
 // Copyright (c) 2016 Intel Corporation
 //
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+// SPDX-License-Identifier: Apache-2.0
 //
 
 package hyperstart