cmd/go/internal/vcs: use git log to avoid unnecessary objects
"git show" by default shows the diff from the previous commit. "-s"
suppress all output from the diff machinery. But it will still try to
fetch the relevant objects, which may be unavailable if the repository
is a partial clone.
Use "git log" instead, which only needs the commit object.
Fixes #65339
Change-Id: I766a680321cd22d5fdbd08d24cb777ef964bdb7c
GitHub-Last-Rev:
87a8ba435251f2a72aa18f2820ccb8ea5b379d69
GitHub-Pull-Request: golang/go#65341
Reviewed-on: https://go-review.googlesource.com/c/go/+/559075
Auto-Submit: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>