Revert "grid.promise: check is promise is alive more often to speed up a bit"

This reverts commit f03ce7ee

slapos/grid/promise/__init__.py

@@ -483,7 +483,7 @@ class PromiseLauncher(object):
 
     self.logger.info("Checking promise %s..." % promise_name)
     queue_item = None
-    sleep_time = 0.05
+    sleep_time = 0.1
     increment_limit = int(self.promise_timeout / sleep_time)
     execution_time = self.promise_timeout
     ps_profile = False