Fix minor problem with autotest permissions

src/scripts/sync_build_test.sh

 #!/bin/bash
 
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Script to sync your checkout, build a Chromium OS image, and test it all
 # with one command.  Can also check out a new Chromium OS checkout and
 # perform a subset of the above operations.
 #
@@ skipping 441 matching lines @@
     if [[ -e "autotest.tgz" || -e "autotest.tar.bz2" ]]; then
       # pull in autotest
       local dir="${FLAGS_chroot}/build/${FLAGS_board}/usr/local"
       local tar_args="xzf"
       local tar_name="${dl_dir}/autotest.tgz"
       if [[ -e "autotest.tar.bz2" ]]; then
         tar_args="xjf"
         tar_name="${dl_dir}/autotest.tar.bz2"
       fi
       sudo rm -rf "${dir}/autotest"
-      cd ${dir}
+      # Expand in temp directory as current user, then move it as
+      # root to keep local user ownership
+      run_phase "Unpacking buildbot autotest cross-compiled binaries" \
+        tar ${tar_args} "${tar_name}"
       run_phase "Installing buildbot autotest cross-compiled binaries" \
-        sudo tar ${tar_args} "${tar_name}"
+        sudo mv autotest ${dir}
     fi
   fi
   chdir_relative .
   run_phase "Removing downloaded image" rm -rf "${dl_dir}"
 }
 
 
 function main() {
   assert_outside_chroot
   assert_not_root_user
@@ skipping 109 matching lines @@
   fi
 
   trap - EXIT
   echo "Successfully used ${FLAGS_top} to:"
   describe_steps
   show_duration
 }
 
 
 main $@