Include the issuer's certificate only when available

When pesign generates a signature, it also includes the issuer's certificate.
In SUSE build server, we only import the signer's certificate and pesign
complaint the issuer's certificate was not found. Per Authenticode PE, the
root certificate is typically not included in the certificate list, so I
modified pesign a bit to include the issuer's certificate only when available.
Please check the attached patch.

Besides the issuer's certificate, I also found find_named_certificate() didn't
handle the certificate list properly and it may cause segfault if "node->cert"
is not valid. The patch also fixes this issue.
Try harder to figure out if this is RHEL.

Signed-off-by: Peter Jones <pjones@redhat.com>
Don't use ASCII mode for RHEL certificate imports.

Signed-off-by: Peter Jones <pjones@redhat.com>
Apparently if something goes wrong on the HSM, we wind up with 0-size.

Handle zero-sized output by erroring in the rpm macro.  Eventually we
should make sure pesign is throwing an error there too.

Signed-off-by: Peter Jones <pjones@redhat.com>
Use --force when we've got a sattrs blob from mktemp()

Signed-off-by: Peter Jones <pjones@redhat.com>
Remove errant results from signing.
Bump version to 0.107

Signed-off-by: Peter Jones <pjones@redhat.com>