sync common.notifier.* from oslo

Change-Id: Ifa42b07e3de7c6decaed22f0ddf06b4fc1c13cad
sync common.periodic_task from oslo

Change-Id: I48893105877d18534099096a13da852e3e3ecbc2
sync common.service from oslo

Change-Id: I2823451380157d2962d35a3c4b079140abad5537
Merge "sync common.notifier.* from oslo"
Merge "sync common.periodic_task from oslo"
Merge "sync common.service from oslo"