cmd/go: avoid password prompts in TestScript/mod_get_private_vcs
In some cases, this test would prompt for interactive SSH passwords in
order to authenticate to github.com over SSH. Setting GIT_SSH_COMMAND
to /bin/false prevents that, while still provoking the desired Git
failure mode.
Updates #44904.
Change-Id: Idc9fe9f47d2ccb6c8a4ea988b73d9c8c774e4079
Reviewed-on: https://go-review.googlesource.com/c/go/+/300156
Trust: Bryan C. Mills <bcmills@google.com>
Trust: Kevin Burke <kev@inburke.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Kevin Burke <kev@inburke.com>