Hack one ssl test case to pass with current LibreSSL.

Hack one ssl test case to pass with current LibreSSL.

With LibreSSL, our test of error logging for cert chain depths > 0
reports the wrong certificate.  This is almost certainly their bug
not ours, so just tweak the test to accept their answer.

No back-patch needed, since this test case wasn't enabled before
e0f373ee4.

Reported-by: Thomas Munro <thomas.munro@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CA+hUKG+fLqyweHqFSBcErueUVT0vDuSNWui-ySz3+d_APmq7dw@mail.gmail.com