[autotest] fix a bug in rpm_dispatcher

This fixed a bug introduced in CL:212357
We need to stop trying if an rpm power state request
failed.

BUG=chromium:212346
TEST=unittest; Integration tests with other cls in this series, set
up a local rpm server and power cycle devices. Make sure
the bug goes away.

Change-Id: I39d9e7fce464a762bca4847de33e7e2c59317e5b
Reviewed-on: https://chromium-review.googlesource.com/216840
Reviewed-by: Dan Shi <dshi@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Tested-by: Fang Deng <fdeng@chromium.org>
Commit-Queue: Fang Deng <fdeng@chromium.org>
diff --git a/site_utils/rpm_control_system/rpm_dispatcher.py b/site_utils/rpm_control_system/rpm_dispatcher.py
index 25fca6d..7adfded 100755
--- a/site_utils/rpm_control_system/rpm_dispatcher.py
+++ b/site_utils/rpm_control_system/rpm_dispatcher.py
@@ -128,13 +128,10 @@
         powerunit_info = utils.PowerUnitInfo(**powerunit_info_dict)
         logging.info('Received request to set device: %s to state: %s',
                      powerunit_info.device_hostname, new_state)
-        result = False
-        while not result:
-            rpm_controller = self._get_rpm_controller(
-                    powerunit_info.powerunit_hostname,
-                    powerunit_info.hydra_hostname)
-            result = rpm_controller.queue_request(powerunit_info, new_state)
-        return result
+        rpm_controller = self._get_rpm_controller(
+                powerunit_info.powerunit_hostname,
+                powerunit_info.hydra_hostname)
+        return rpm_controller.queue_request(powerunit_info, new_state)
 
 
     def _get_rpm_controller(self, rpm_hostname, hydra_hostname=None):