Rather than only parsing/verifying one SignerInfo in the SignerInfos
field of the PKCS7 stucture, allow the ability to parse and verify more
than one signature. Verification will return success if any of the signatures
produce a match.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Nick Child <nick.child@ibm.com>