CMS_SharedInfo_encode() can also return a negative error value, but this
is not checked in the current check, only the zero error return value is
covered. A previous PR [1] fixed the other caller's check of
CMS_SharedInfo_encode in this file, but it seems like this place was
missed. Fix it by changing the check to <= 0.
[1] a752fc4da5
CLA: trivial
Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20181)
ba061818e9