Updated PNaCl tool revision update script to use package_version.
Updated PNaCl tool revision update script to use package_version.

Since TOOL_REVISION is being deprecated, the PNaCl tool revision update
script should be updated to utilitize the new revision files instead.

BUG=
R=jfb@chromium.org

Review URL: https://codereview.chromium.org/248073002

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@13073 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client