Fix a possible NULL pointer dereference in create_cert_store()

Fix a possible NULL pointer dereference in create_cert_store()

In create_cert_store(), X509_STORE_new() is called and there is a
dereference of it in following function X509_STORE_add_lookup()
without check, which could lead to NULL pointer dereference.

Fix this by adding a NULL check of X509_STORE_new()

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18057)