Per review comment, set server's zerocopy option to j_p->valueint instead of 1

src/iperf_api.c

@@ -2163,7 +2163,7 @@ get_parameters(struct iperf_test *test)
 	if ((j_p = cJSON_GetObjectItem(j, "repeating_payload")) != NULL)
 	    test->repeating_payload = 1;
 	if ((j_p = cJSON_GetObjectItem(j, "zerocopy")) != NULL)
-	    test->zerocopy = 1;
+	    test->zerocopy = j_p->valueint;
 #if defined(HAVE_DONT_FRAGMENT)
 	if ((j_p = cJSON_GetObjectItem(j, "dont_fragment")) != NULL)
 	    test->settings->dont_fragment = j_p->valueint;