llvm_tools: more informative message when checking out llvm-project-copy

We keep a clone of the LLVM repository, which we create if it did not
already exist. This takes a while, so we inform the user. However, the
message did not specify where we are cloning to or why. This change
makes the message take the form:

  Checking out LLVM to '<path>'
  so that we can map between commit hashes and revision numbers.
  This may take a while, but only has to be done once.

BUG=b:192699914
TEST=ran llvm_tools/get_llvm_hash.py with a few parameters

Change-Id: I86d83f03ab293c5cfb3014e80175c674740a2818
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/3078689
Tested-by: Bob Haarman <inglorion@chromium.org>
Reviewed-by: Jordan R Abrahams <ajordanr@google.com>
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
1 file changed