Merge lp://staging/~qzhang/lava-dispatcher/another-inject-kernel into lp://staging/lava-dispatcher

Another injecting kernel, use l-h-r now.
1. use linaro-hwpack-replace to get a new hwpack with new kernel before deployment.
2. tested once and pass
3. only support new kernel in deb format in normal image and tarball format in Android image.
4. job file like:
  "actions": [
    {
      "command": "deploy_linaro_image",
      "parameters":
        {
          "rootfs":
"http://snapshots.linaro.org/11.05-daily/linaro-nano/20110612/0/images/tar/nano-n-tar-20110612-0.tar.gz",
          "hwpack":
"http://snapshots.linaro.org/11.05-daily/linaro-hwpacks/lt-mx53loco/20110609/0/images/hwpack/hwpack_linaro-lt-mx53loco_20110609-0_armel_supported.tar.gz",
          "kernel_matrix":[
"http://pkgserver/original/linux-image-2.6.38-1000-linaro-lt-mx5_2.6.38-1000.7_armel.deb", "linux-image-2.6.38"]
        }
    },