ECAL DQM harvesting migration and online bugfix

[yiiyama]

The branch name is not quite correct for what this PR is. I'm sorry. This PR synchronizes ECAL DQM with the HEAD of 73X.

[cmsbuild]

A new Pull Request was created by @yiiyama (Yutaro Iiyama) for CMSSW_7_2_X.

Synching 72 with 73

It involves the following packages:

DQM/EcalCommon
DQM/EcalMonitorClient
DQM/EcalMonitorDbModule
DQM/EcalMonitorTasks
DQMOffline/Configuration
DQMOffline/Ecal

The following packages do not have a category, yet:

DQM/EcalMonitorClient
DQM/EcalMonitorDbModule
DQM/EcalMonitorTasks

@nclopezo, @danduggan, @rovere, @cmsbuild, @deguio, @ojeda can you please review it and eventually sign? Thanks.
@argiro, @threus, @rociovilar this is something you requested to watch as well.
You can sign-off by replying to this message having '+1' in the first line of your reply.
You can reject by replying to this message having '-1' in the first line of your reply.
@nclopezo you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[cmsbuild]

+1
Tested at: 95c6e8a
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-5786/38/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-5786/38/summary.html

[deguio]

+1
this is the backport of a fix developed on top of 73. the migration to the DQMEDHarvester is also backported.

[davidlange6]

please change the name of this PR to a meaningful one reflecting it contents for the release notes (and the similar one) if you want it considered for integration. Thanks

[yiiyama]

@davidlange6 The title reflects the content now. Thank you.