add a configuration to choose if you want to receive certificate only or certificate chain

3 jobs for v2.1-acme-draft-16 in 6 minutes and 20 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #449
jessie

00:02:05

failed #450
jessie_backport

00:02:08

failed #451
stretch

00:02:06

 
Name Stage Failure
failed
jessie Test There is an unknown failure, please try again
  File "/builds/adrien/acme-dns-tiny/tests/test_acme_dns_tiny.py", line 45, in assertCertificateChain
self.assertEqual(3, len(certlist))
AssertionError: 3 != 1

----------------------------------------------------------------------
Ran 14 tests in 78.195s

FAILED (failures=3, errors=4)
ERROR: Job failed: exit code 1
failed
stretch Test There is an unknown failure, please try again
  File "/builds/adrien/acme-dns-tiny/tests/test_acme_dns_tiny.py", line 45, in assertCertificateChain
self.assertEqual(3, len(certlist))
AssertionError: 3 != 1

----------------------------------------------------------------------
Ran 14 tests in 81.112s

FAILED (failures=3, errors=4)
ERROR: Job failed: exit code 1
failed
jessie_backport Test There is an unknown failure, please try again
  File "/builds/adrien/acme-dns-tiny/tests/test_acme_dns_tiny.py", line 45, in assertCertificateChain
self.assertEqual(3, len(certlist))
AssertionError: 3 != 1

----------------------------------------------------------------------
Ran 14 tests in 82.007s

FAILED (failures=3, errors=4)
ERROR: Job failed: exit code 1