Stop timeout when plugin fails

The plugin module watchdog timeout has to be stopped when module run
ends with an exception. When it's not, the module together with the rest
API server would be restarted after the timeout exceeds.

smoker/client/__init__.py

@@ -388,7 +388,11 @@ def poll(self, uri, sleep=1):
 
             if not res:
                 if retries == 0:
-                    lg.error("Polling on %s failed after 3 retries" % uri)
+                    lg.error(
+                        "Polling on %s failed after 3 retries. This may "
+                        "happen when a plugin died while waiting for the "
+                        "result. Please retry and check log on the hosts if "
+                        "it happens again." % uri)
                     return False
                 else:
                     retries -= 1

smoker/server/plugins/__init__.py

@@ -557,6 +557,7 @@ def run_module(self, module, **kwargs):
         except Exception as e:
             lg.error("Plugin %s: module execution failed: %s" % (self.name, e))
             lg.exception(e)
+            signal.alarm(0)
             raise
 
         signal.alarm(0)