am 5b4aa6db: Merge change 26315 into eclair

Merge commit '5b4aa6db428263aa0a48ab3efb896df66a852bce' into eclair-plus-aosp

* commit '5b4aa6db428263aa0a48ab3efb896df66a852bce':
  VpnService: use Credentials instead of CertTool.