Description:
------------
https://secure.php.net/downloads.php#gpg-7.1 lists

pub   4096R/7BD5DCD0 2016-05-07
      Key fingerprint = A917 B1EC DA84 AEC2 B568 FED6 F50A BC80 7BD5 DCD0
uid                  Davey Shafik <davey@php.net>

pub   2048R/31CBD89E 2016-12-08
      Key fingerprint = 5289 95BF EDFB A719 1D46  839E F9BA 0ADA 31CB D89E
uid                  Joe Watkins <krakjoe@php.net>

as signatories of the PHP 7.1 releases.

Trying to validate the latest 7.1.13 or 7.1.14 relase fails with error:

gpg: Signature made Tue Jan 30 20:08:39 2018 CET using RSA key ID 70D12172
gpg: Can't check signature: public key not found

RSA key ID 70D12172 corresponds to Sara Golemon, who is listed as a signatory for the 7.2 releases.

Test script:
---------------
mkdir test
cd test

curl -fSL https://secure.php.net/get/php-7.1.13.tar.xz/from/this/mirror -o php.tar.xz
curl -fSL https://secure.php.net/get/php-7.1.13.tar.xz.asc/from/this/mirror -o php.tar.xz.asc

mkdir -m 700 gnupghome
export GNUPGHOME=$PWD/gnupghome

gpg --keyserver ha.pool.sks-keyservers.net --recv-keys 528995BFEDFBA7191D46839EF9BA0ADA31CBD89E
gpg --keyserver ha.pool.sks-keyservers.net --recv-keys A917B1ECDA84AEC2B568FED6F50ABC807BD5DCD0

gpg --batch --verify php.tar.xz.asc php.tar.xz

Expected result:
----------------
gpg reporting that php-7.1.13.tar.xz was signed by eighter 31CBD89E or 7BD5DCD0

Actual result:
--------------
gpg: Signature made Wed Jan  3 03:34:35 2018 CET using RSA key ID 70D12172
gpg: Can't check signature: public key not found