bugfix: ngx_http_lua_ffi_ssl_create_ocsp_request: we did not clear the openssl stack errors in the right place.

Author: agentzh

src/ngx_http_lua_ssl_ocsp.c

@@ -233,8 +233,6 @@ ngx_http_lua_ffi_ssl_create_ocsp_request(const char *chain_data,
     X509_free(cert);
     BIO_free(bio);
 
-    ERR_clear_error();
-
     return NGX_OK;
 
 failed:
@@ -255,6 +253,8 @@ ngx_http_lua_ffi_ssl_create_ocsp_request(const char *chain_data,
         BIO_free(bio);
     }
 
+    ERR_clear_error();
+
     return rc;
 
 #endif  /* NGX_HTTP_LUA_USE_OCSP */