yakkety tests fail with "Signature verification error: debsig: No applicable policy found"

click's tests have started failing around 2016-07-16: http://autopkgtest.ubuntu.com/packages/c/click/yakkety/amd64/

They fail on

test_debsig_install_valid_signature (click.tests.integration.test_signatures.TestSignatureVerification) ... gpg: WARNING: unsafe ownership on homedir `/tmp/autopkgtest.2cHHB1/build.hVC/click-0.4.43+16.04.20160203/click/tests/integration/data/origin-keyring'
gpg: WARNING: unsafe ownership on homedir `/tmp/autopkgtest.2cHHB1/build.hVC/click-0.4.43+16.04.20160203/click/tests/integration/data/origin-keyring'
Cannot install /tmp/tmp3xuj04d3/org.example.debsig-valid-sig_1.0_all.click: Signature verification error: debsig: No applicable policy found.

ERROR

======================================================================
ERROR: test_debsig_install_valid_signature (click.tests.integration.test_signatures.TestSignatureVerification)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/autopkgtest.2cHHB1/build.hVC/click-0.4.43+16.04.20160203/click/tests/integration/test_signatures.py", line 188, in test_debsig_install_valid_signature
    path_to_click])
  File "/usr/lib/python3.5/subprocess.py", line 581, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['/usr/bin/click', 'install', '--user=root', '/tmp/tmp3xuj04d3/org.example.debsig-valid-sig_1.0_all.click']' returned non-zero exit status 1