fix a bug about getting null machine in HeartBeatAlert
Merge pull request #586 from jialinsun/master

modify scheduledManager
Merge pull request #585 from leonindy/master

fix a bug about getting null machine in HeartBeatAlert
change alteration period to 30 minutes when generating summary message
Merge pull request #587 from leonindy/master

change alteration period to 30 minutes when generating summary message
Merge branch 'master' of https://github.com/dianping/cat