Run gpg in batch mode

[wadells]

Summary

This fixes a release bug when gpg attempts to sign repomd.xml when a signature is already present.

Contributes to #9726.

Testing Done

I set up a docker container with a repomd.xml.asc already in place, and verify the gpg: cannot open '/dev/tty': No such device or address message showed up. Then I added the fix.

Dockerfile and docker run

walt@work:/tmp/rpm$ ls
Dockerfile  gpg.tar.base64  repomd.xml  sign.sh
walt@work:/tmp/rpm$ cat Dockerfile 
from centos:8
copy . /
entrypoint ["bash", "/sign.sh"]
walt@work:/tmp/rpm$ cat sign.sh 
export GNUPGHOME=/tmp/gnupg
mkdir -p -m0700 $GNUPGHOME
cat gpg.tar.base64 | base64 -d | tar -xzf - -C $GNUPGHOME
chown -R root:root $GNUPGHOME
# rm -f /dev/tty
gpg --detach-sign --armor --batch --yes /repomd.xml
echo foo >> /repomd.xml.asc
cat /repomd.xml.asc
gpg --detach-sign --armor --batch --yes /repomd.xml
cat /repomd.xml.asc
walt@work:/tmp/rpm$ docker build . -t foo && docker run foo
Sending build context to Docker daemon  14.85kB
Step 1/3 : from centos:8
 ---> 300e315adb2f
Step 2/3 : copy . /
 ---> 8fdf24cd2d92
Step 3/3 : entrypoint ["bash", "/sign.sh"]
 ---> Running in ccf7b521ad04
Removing intermediate container ccf7b521ad04
 ---> 6c7a920b804b
Successfully built 6c7a920b804b
Successfully tagged foo:latest
-----BEGIN PGP SIGNATURE-----

iQIzBAABCAAdFiEEDF6LpWWOMg0bAxF5yH7VOmKCxBEFAmHc8eEACgkQyH7VOmKC
xBEnFxAAtrxEHVuaThN2ytETZaQXYV4y+X11n750quudTydca1Sxlr7CzBxrzjPM
3oqHj6TOQjYUqgkk7r/wOIKQo9Nx3UM+5WU/LKnFcjt5FNhpvw6EkHGmovBWF64A
tG/175SWQIyEKHrL+zXtTxOsxvLhuJSq7JntWVJt34VCs/LNl3xYas4H0utNcRzO
nuuOlbIUZ6xgHhyazHTNlBm0S2pT2DtcnnB8opueAYj09DooGFmzFh1p5BB7aNtv
aIEcjuGV5bHdSp6LPsDJOOIgBT/KKuOO484YOS6adk2f4rwgYjbQLqSlI6Yd84GJ
7/26q/2HLAUQAToS51OVYmLvatgcTYLF6HtgAW/8nPt6umP4gSq+IFkvq2A9T7Au
RPN/mBZ3o1Z4lfdATnoDxm4J/ACZk3gC7uAF1dOjlCYy+0Ewdy+V0yQA9TUj6FiF
Ef4pB50yUcSAOD7q9bFJZU4yaQgKdzs780TGEBnxlcxnb42jhjqhduiE1zRieDTk
xNtd53oicVpFfPuhCjI8BbQvqg9n0U+rgLeAgtc7KSZtvUut6TNNk/dDltARXE6t
tCdR9Xhn0JjJKsqcGmzyngXSmzS8ue9VYtxgOmVjKm573PwCs9ZWuAkIHlX9bbja
wxuN/+hAdSppFXIzu53jruP5RAYziuen2d1kwQqrrgzbJ6n59hw=
=IT+Q
-----END PGP SIGNATURE-----
foo
-----BEGIN PGP SIGNATURE-----
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=IT+Q
-----END PGP SIGNATURE-----