llvm_tools: check for uncommited changes before cherry-picks

Exit when uncommited changes in chromiumos-overlay repo is detected.

BUG=chromium:1057428

TEST=local tests.

Change-Id: I6dacfb67028036b415672c8fba622b49c4ae8b76
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2321560
Tested-by: Jian Cai <jiancai@google.com>
Reviewed-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Luis Lozano <llozano@chromium.org>
1 file changed