Fix SSL015 CANARIES condition

[Marsman1996]

According to the code in MAGMA_ENABLE_FIXES

if (p7->d.ptr == NULL) {
    PKCS7err(PKCS7_F_PKCS7_DATAINIT, PKCS7_R_NO_CONTENT);
    return NULL;
}

and other 2 CANARIES code,

magma/targets/openssl/patches/bugs/SSL015.patch

Line 40 in 75d1ae7

+ MAGMA_LOG("%MAGMA_BUG%", MAGMA_OR(p7 == NULL, p7->d.ptr == NULL));

magma/targets/openssl/patches/bugs/SSL015.patch

Line 61 in 75d1ae7

+ MAGMA_LOG("%MAGMA_BUG%", MAGMA_OR(p7 == NULL, p7->d.ptr == NULL));

p7->d.ptr should also be null when vulnerability is triggered.