tools/git-sync-deps: enforce commit hash in DEPS, not tags or branches

Change variable name to reflect that.

Also, pass '--no-checkout' to git-clone to suppress "warning: remote
HEAD refers to nonexistent ref, unable to checkout" error message.

Also, change '@' to '>' in verbose output if anything changes in the
repositories.

Change-Id: I27d0b026d121c163e378f34ab2bbe81233ddba1a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/252177
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
1 file changed