[http] Accept Content-Length header with trailing whitespace

At least one HTTP server (Google's OCSP responder) has been observed
to generate a Content-Length header with trailing whitespace.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[ocsp] Handle OCSP responses that don't provide certificates

Certificate authorities are not required to send the certificate used
to sign the OCSP response if the response is signed by the original
issuer.

Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[crypto] Remove dynamically-allocated storage for certificate name

iPXE currently allocates a copy the certificate's common name as a
string.  This string is used by the TLS and CMS code to check
certificate names against an expected name, and also appears in
debugging messages.

Provide a function x509_check_name() to centralise certificate name
checking (in preparation for adding subjectAlternativeName support),
and a function x509_name() to provide a name to be used in debugging
messages, and remove the dynamically allocated string.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[crypto] Remove dynamically-allocated storage for certificate OCSP URI

Signed-off-by: Michael Brown <mcb30@ipxe.org>