1. mp.set_start_method('spawn') commented out from scripts/uncloud

2. uncloud.shared moved under uncloud.common
3. Refactoring in etcd_wrapper e.g timeout mechanism removed and few other things
4. uncloud-{scheduler,host} now better handle etcd events in their block state (waiting for requests to come)

scripts/uncloud

@@ -45,7 +45,7 @@ if __name__ == '__main__':
         # i.e inheriting few things from parent process etcd3 module
         # errors out, so the following command configure multiprocessing
         # module to not inherit anything from parent.
-        mp.set_start_method('spawn')
+        # mp.set_start_method('spawn')
         arguments = vars(args)
         try:
             name = arguments.pop('command')