Handle GnuPG 2.4.9

[puck]

GnuPG 2.4.9 fixes possible memory corruption in armor parsing[0] it appears that this has also changed the warnings emitted. This test now fails:

  t/seecurity/CVE-2012-4735-incoming-encryption-header.t .. # GnuPG --homedir /tmp/xqR91djkdB
  ok 1 - created a ticket
  ok 2 - loaded ticket
  ok 3 - Found the right attachment
  ok 4 - Incoming encryption header is removed
  ok 5 - Incoming signature header is removed
  ok 6 - created a ticket
  ok 7 - GnuPG warning
  ok 8 - GnuPG warning
  not ok 9 - GnuPG warning

  #   Failed test 'GnuPG warning'
  #   at t/security/CVE-2012-4735-incoming-encryption-header.t line 65.
  #                   'Failure during GnuPG gpg-exit: Failed to gpg-exit
  # '
  #     doesn't match '(?^:Failure during GnuPG data: No data has been found\. The reason is 'No armored data')'
  ok 10 - loaded ticket
  ok 11 - Found the right attachment
  ok 12 - Incoming encryption header is removed
  ok 13 - Incoming signature header is removed
  ok 14 - no warnings
  1..14

These are the warnings emitted:

  $VAR1 = [
            'gpg: keybox \'/tmp/rRZPP1xcq3/pubring.kbx\' created
  gpg: invalid radix64 character 5F skipped
  gpg: invalid radix64 character 5F skipped
  gpg: invalid radix64 character 2E skipped
  gpg: [don\'t know]: invalid packet (ctb=4e)
  ',
            'Failure during GnuPG data: No data has been found. The reason is \'Invalid packet found\'
  ',
            'Failure during GnuPG gpg-exit: Failed to gpg-exit
  '
          ];

Let's only look for the 'No armored data' on < 2.4.9.

Reported in Debian as part of our regular QA processes:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1130943

[0] https://github.com/gpg/gnupg/blob/6cd241007f390a4be8f18982783e79e7cfb42c5f/NEWS#L1