PKCS7: Remove one of the duplicate checks

There are two consecutive identical checks "if (i <= 0)".
We can remove one of them to make the code clear.

CLA: trivial

Signed-off-by: Jiasheng Jiang <jiasheng@purdue.edu>

Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/23741)

crypto/pkcs7/pk7_smime.c

@@ -290,9 +290,8 @@ int PKCS7_verify(PKCS7 *p7, STACK_OF(X509) *certs, X509_STORE *store,
             if (!(flags & PKCS7_NOCRL))
                 X509_STORE_CTX_set0_crls(cert_ctx, p7->d.sign->crl);
             i = X509_verify_cert(cert_ctx);
-            if (i <= 0)
-                j = X509_STORE_CTX_get_error(cert_ctx);
             if (i <= 0) {
+                j = X509_STORE_CTX_get_error(cert_ctx);
                 ERR_raise_data(ERR_LIB_PKCS7, PKCS7_R_CERTIFICATE_VERIFY_ERROR,
                                "Verify error: %s",
                                X509_verify_cert_error_string(j));