GPG keys intermittently failing during build

[hspedro]

Steps to reproduce:

• Clone repo (current HEAD c19e8e1)
• Build docker image (I've only tested 3.4 but probably happen in 3.3 as well)

Rate:

• 3 out of 5

Error:

+ mktemp -d
+ export GNUPGHOME=/tmp/tmp.OSOZJzZVdd
+ gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4
gpg: keybox '/tmp/tmp.OSOZJzZVdd/pubring.kbx' created
gpg: keyserver receive failed: Cannot assign requested address
The command '/bin/sh -c set -eux;       savedAptMark="$(apt-mark showmanual)";  apt-get update;       apt-get install -y --no-install-recommends               dirmngr                 gnupg   ;       rm -rf /var/lib/apt/lists/*;           dpkgArch="$(dpkg --print-architecture | awk -F- '{ print $NF }')";    export GOSU_VERSION='1.10';      wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$dpkgArch";   wget -O /usr/local/bin/gosu.asc "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$dpkgArch.asc";   export GNUPGHOME="$(mktemp -d)";        gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4;     gpg --batch --verify /usr/local/bin/gosu.asc /usr/local/bin/gosu;        gpgconf --kill all;     rm -r "$GNUPGHOME" /usr/local/bin/gosu.asc;    chmod +x /usr/local/bin/gosu;   gosu nobody true;             export TINI_VERSION='0.18.0';    wget -O /usr/local/bin/tini "https://github.com/krallin/tini/releases/download/v$TINI_VERSION/tini-$dpkgArch";         wget -O /usr/local/bin/tini.asc "https://github.com/krallin/tini/releases/download/v$TINI_VERSION/tini-$dpkgArch.asc";         export GNUPGHOME="$(mktemp -d)";       gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys 6380DC428747F6C393FEACA59A84159D7001A4E5;       gpg --batch --verify /usr/local/bin/tini.asc /usr/local/bin/tini;       gpgconf --kill all;    rm -r "$GNUPGHOME" /usr/local/bin/tini.asc;     chmod +x /usr/local/bin/tini;   tini -h;      apt-mark auto '.*' > /dev/null;  [ -z "$savedAptMark" ] || apt-mark manual $savedAptMark;        apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false' returned a non-zero code: 2

As per similar issues on tianon/gosu#35 and nodejs/docker-node#632. So, depending on the key server it might get an ipv6 address that can cause issues due
to uncompat or it could just be other key server incosistencies, docker-library/official-images#4006 (comment).

[wglambert]

docker-library/official-images#4252 (comment)

TLDR; GPG servers are extremely flaky . . .

This is what we do for GPG issues docker-library/official-images#4252 (comment)