redfishpower: reduce polling interval in test mode

Problem: When in test mode, the status polling interval is still
set to 1 second.  This can slow down tests.

Reduce the status polling interval to 1 millisecond when in test mode.

src/redfishpower/redfishpower.c

@@ -1161,6 +1161,11 @@ int main(int argc, char *argv[])
             free(hostname);
         }
         hostlist_iterator_destroy(itr);
+
+        /* under test mode we can make the polling interval a lot smaller
+         * lets put it to a millisecond.
+         */
+        status_polling_interval = 1000;
     }
 
     shell(mh);