Merge request1231into root6branch

[wmtan]

This is a snapshot of pull request 1231, but intended for the ROOT 6 branch instead of the main 7_0_X branch.
This will fix the compilation error in RecoVertex/BeamSpotProducer. It may be a long wait until pull request 1231 is pulled into a main release. I tried picking out just the minimal change for the compilation error, but that was not straightforward.

[cmsbuild]

A new Pull Request was created by @wmtan for CMSSW_7_0_ROOT6_X.

Merge request1231into root6branch

It involves the following packages:

Calibration/TkAlCaRecoProducers
DQM/BeamMonitor
RecoVertex/BeamSpotProducer
DQM/Physics
DQM/DTMonitorModule

@thspeer, @demattia, @danduggan, @rovere, @cmsbuild, @nclopezo, @rcastello, @deguio, @slava77, @eliasron can you please review it and eventually sign? Thanks.
@cerati, @GiacomoSguazzoni, @rovere 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.

[wmtan]

David,
Please merge this unless it causes unforeseen problems. This allows RevoVertex/BeamSpotProducer to compile.

[davidlt]

Trusting that you have tested it locally :) Merging.

[wmtan]

Yes, this pull request, plus checkdeps -a, all compiles against the latest ROOT6 IB.