setup_board: Remove LIBC_VERSION hack.

Now that we store the current version of libc in the sysroot cache, we
can drop the hack from setup_board.

BUG=None
TEST=trybots.

Change-Id: I61ba6c4d5faa9fa794976d9f850d1a31c1215e7a
Reviewed-on: https://chromium-review.googlesource.com/265934
Trybot-Ready: Bertrand Simonnet <bsimonnet@chromium.org>
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>
1 file changed