Removed empty/unused functions from DBService

[Dr15Jones]

To make future maintenance easier and avoid possible thread-safety
issues I removed empty functions and the one unused function
which returned a pointer to the internals of the Service.

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for CMSSW_7_1_X.

Removed empty/unused functions from DBService

It involves the following packages:

RecoLuminosity/LumiProducer

@nclopezo, @cmsbuild, @anton-a, @thspeer, @slava77, @Degano can you please review it and eventually sign? Thanks.
You can sign-off by replying to this message having '+1' in the first line of your reply.
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@nclopezo, @ktf you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[Dr15Jones]

What happens to this service if multiple threads call DBService::connectReadOnly or DBService::disconnect simultaneously? Similarly, are the coral::ISessionProxy classes thread-safe?

[cmsbuild]

+1
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-2734/371/summary.html

[anton-a]

+1
Does not affect reco

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_1_X IBs unless changes (tests are also fine). @nclopezo, @ktf can you please take care of it?