Return code of curl_multi_add_handle is not handled properly

[bitscher]

Static analysis shows that return value of the function call to curl_multi_add_handle in function add_to_curlm is not handled properly.

mod_md/src/md_curl.c

Lines 448 to 459 in 2f7df2d

	static void add_to_curlm(md_http_request_t *req, CURLM *curlm)
	{
	md_curl_internals_t *internals = req->internals;
	assert(curlm);
	assert(internals);
	if (internals->curlm == NULL) {
	internals->curlm = curlm;
	}
	assert(internals->curlm == curlm);
	curl_multi_add_handle(curlm, internals->curl);
	}

Return codes should probably be forwarded by add_to_curlm and handled in the calling-scope in function md_curl_multi_perform alongside other errors.

mod_md/src/md_curl.c

Lines 527 to 539 in 2f7df2d

	if (APR_SUCCESS != (rv = internals_setup(req))) {
	if (req->cb.on_status) req->cb.on_status(req, rv, req->cb.on_status_data);
	md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, rv, p,
	"multi_perform[%d reqs]: setup failed", requests->nelts);
	APR_ARRAY_PUSH(http_spares, md_http_t*) = sub_http;
	goto leave;
	}
	APR_ARRAY_PUSH(requests, md_http_request_t*) = req;
	add_to_curlm(req, curlm);
	md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, rv, p,
	"multi_perform[%d reqs]: added request", requests->nelts);
	}