tests: add test cases for import without uid

tests: add test cases for import without uid

This commit adds a test case that does the following, in order:
- Import of a primary key plus user id
- Check that import of a subkey works, without a user id present in the
imported key
- Check that import of a subkey revocation works, without a user id or
subkey binding signature present in the imported key
- Check that import of a primary key revocation works, without a user id
present in the imported key

--

Note that this test currently fails.  The following changesets will
fix gpg so that the tests pass.

GnuPG-Bug-id: 4393
Signed-Off-By: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
Gbp-Pq: Topic import-merge-without-userid
Gbp-Pq: Name tests-add-test-cases-for-import-without-uid.patch