cmd/go: disable go get chatter about git config

[rsc]

This looks like bad debugging prints:

g% go get -u rsc.io/benchstat
# cd /Users/rsc/g/src/rsc.io/benchstat; git config remote.origin.url
# cd /Users/rsc/g/src/rsc.io/benchstat; git config remote.origin.url
g%

[dsymonds]

I can't reproduce this at tip. Near as I can tell, those lines come from src/cmd/go/vcs.go:309, but are only printed when the command fails. That'll happen if, for instance, you don't have a remote called "origin" in an existing repository.

[c9s]

Can't reproduce too. at commit 80864cf1f7804e23be215245a70d70efd1116bb4

[c9s]

I can now reproduce it, I dropped the origin remote from rsc.io/benchstat and re-run command again, it shows the same message.

go get -u rsc.io/benchstat
# cd /Users/c9s/src/rsc.io/benchstat; git config remote.origin.url
# cd /Users/c9s/src/rsc.io/benchstat; git pull --ff-only
fatal: 'origin' does not appear to be a git repository
fatal: Could not read from remote repository.

[c9s]

The error message is improved in this CL: https://go-review.googlesource.com/10475

[gopherbot]

CL https://golang.org/cl/10475 mentions this issue.

[rsc]

Fixes syntax was wrong.