ndn_sig_verifier_verify_data: accept certificate name in KeyLocator.Name

[yoursunny]

Currently, ndn_sig_verifier_verify_data can only accept key name in KeyLocator.Name field.

ndn-lite/app-support/ndn-sig-verifier.c

Line 292 in d60a114

uint32_t keyid = key_id_from_key_name(&data.signature.key_locator_name);

It should be changed to accept either key name or certificate name.
See #72.