trousers: stop following links for system.data file

This is based on upstream commit https://sourceforge.net/p/trousers/trousers/ci/e74dd1d96753b0538192143adf58d04fcd3b242b/. Trousers code in ChromeOS and upstream has diverged significantly enough that the upstream patch cannot be applied as-is. Only the 1st chunk in that commit is applicable to this issue, and is included in this CL.

BUG=b:268250649
TEST=CQ

Change-Id: I406f978dd277df3ed431fa63a3520e39b7feb327
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/trousers/+/4373796
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Leo Lai <cylai@google.com>
Reviewed-by: Yi Chou <yich@google.com>
Commit-Queue: Andrey Pronin <apronin@chromium.org>
Tested-by: Andrey Pronin <apronin@chromium.org>