Coverity CID 1444951: Null pointer dereferences

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8888)

crypto/ex_data.c

@@ -152,7 +152,7 @@ int crypto_get_ex_new_index_ex(OPENSSL_CTX *ctx, int class_index, long argl,
     OSSL_EX_DATA_GLOBAL *global = openssl_ctx_get_ex_data_global(ctx);
 
     if (global == NULL)
-        goto err;
+        return -1;
 
     ip = get_and_lock(ctx, class_index);
     if (ip == NULL)