tools/release.sh failed on macOS 10.12

Version: master
Platform: macOS 10.12
Subsystem: tools

after signing a tag for a release, the release script does some magic to sign the SHASUMS256.txt file.

It calls git tag -v $version 2>&1 | grep 'key ID' | awk '{print $NF}'. (https://github.com/nodejs/node/blob/v6.7.0/tools/release.sh#L72)

The output of that command does not return anything on my machine using git v2.10.0. If I use the builtin git provided by apple (git v2.8.4), then the script works properly.

Here are the outputs from git tag -v v6.7.0:

With git v2.10.0:

$ git tag -v v6.7.0
object d87ad0ceea3f8ecf14b15cf95776fdbb277e0f07
type commit
tag v6.7.0
tagger Evan Lucas <evanlucas@me.com> 1475021173 -0500

2016-09-27 Node.js v6.7.0 (Current) Release
Git-EVTag-v0-SHA512: f36f72e58f83a6e254d4e43e0249b82db8b6f7f2bb9fd6b847b5f2e49843c6a47e0299363d5a6bebd46dc6af74ca8b02c06c932180be25252b12c5be37c8d8d9
gpg: Signature made Tue Sep 27 19:06:18 2016 CDT
gpg:                using RSA key B63B535A4C206CA9
gpg: Good signature from "Evan Lucas <evanlucas@me.com>" [ultimate]
gpg:                 aka "Evan Lucas <evanlucas@keybase.io>" [ultimate]

With git v2.8.4:

$ /usr/bin/git tag -v v6.7.0
object d87ad0ceea3f8ecf14b15cf95776fdbb277e0f07
type commit
tag v6.7.0
tagger Evan Lucas <evanlucas@me.com> 1475021173 -0500

2016-09-27 Node.js v6.7.0 (Current) Release
Git-EVTag-v0-SHA512: f36f72e58f83a6e254d4e43e0249b82db8b6f7f2bb9fd6b847b5f2e49843c6a47e0299363d5a6bebd46dc6af74ca8b02c06c932180be25252b12c5be37c8d8d9
gpg: Signature made Tue Sep 27 19:06:18 2016 CDT using RSA key ID 4C206CA9
gpg: Good signature from "Evan Lucas <evanlucas@me.com>" [ultimate]
gpg:                 aka "Evan Lucas <evanlucas@keybase.io>" [ultimate]

I am working on a proposed fix that works for both.

/cc @nodejs/release