Make rigctld powerstat query only when able and ETIMEOUT occurs

https://github.com/Hamlib/Hamlib/issues/1085

tests/rigctld.c

@@ -1237,9 +1237,12 @@ void *handle_socket(void *arg)
 
             if (retcode != 0) { rig_debug(RIG_DEBUG_VERBOSE, "%s: rigctl_parse retcode=%d\n", __func__, retcode); }
             // update our power stat in case power gets turned off
+            if (retcode == -RIG_ETIMEOUT && my_rig->caps->get_powerstat) // if we get a timeout we might be powered off
+            {
                 rig_get_powerstat(my_rig, &powerstat);
                 rig_powerstat = powerstat;
             }
+        }
         else
         {
             retcode = -RIG_EIO;