Port back from ROOT6 IB for commonality (DB/ALCA)

[wmtan]

This PR ports back simple changes made in CMSSW_7_4_ROOT6_X in the DB and ALCA L2 categories that are desirable or harmless for CMSSW_7_4_X, in order to increase code commonality. All affected files will be identical in the two releases after this PR is merged. Changes were successfully tested with the short relval matrix.
The changes are:

1. removal of unnecessary typedef keyword
2. addition of enum specifications in XML spec files (needed for ROOT6)
3. addition of typedef specifications in XML files (needed for ROOT6)
4. removal of unneeded link dependency
5. removal of unneeded header include
6. modifications to white space (mostly incidental)

[cmsbuild]

A new Pull Request was created by @wmtan for CMSSW_7_4_X.

Port back from ROOT6 IB for commonality (DB/ALCA)

It involves the following packages:

CondFormats/Common
CondFormats/DTObjects
CondFormats/EcalObjects
CondFormats/PhysicsToolsObjects

@diguida, @cerminar, @cmsbuild, @nclopezo, @ggovi, @mmusich can you please review it and eventually sign? Thanks.
@apfeiffer1, @argiro 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.
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@Degano you are the release manager for this.
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[cmsbuild]

+1
Tested at: ee9ab20
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-8394/3621/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-8394/3621/summary.html