Do not treat asynDisconnected as an error

src/sinqAxis.cpp

@@ -266,7 +266,8 @@ asynStatus sinqAxis::forcedPoll(bool *moving) {
     went wrong and the motor has a status problem. Otherwise, delete the error
     message entry which is currently in the paramLib.
     */
-    if (poll_status != asynSuccess || waitingMessage[0] != '\0') {
+    if ((poll_status != asynSuccess && poll_status != asynDisconnected) ||
+        waitingMessage[0] != '\0') {
         /*
         If doPoll cleared the error message paramLib entry, but an old message
         is still waiting, set the old message.