tests/certs: rebuild certificates with modified key usage bits

The certificates were missing the digitalSignature and keyAgreement
usage types, of which at least digitalSignature was checked by CyaSSL.
This caused the test server in test 310 (among others) to fail the
startup verification and therefore run (see
http://curl.haxx.se/mail/lib-2014-07/0303.html).
39 files changed