Exclude duplicate dictionaries in ROOT::Math

In ROOT 6 we are getting a lot of warning messages due to duplicate dictionaries in ROOT::Math.
These are dictionaries that are defined in ROOT itself and also in CMSSW in DataFormats/Math.
This pull request excludes precisely these dictionaries from being defined again in DataFormats/Math.
This eliminates all the warning messages.
Pleas merge this pull request promptly unless there are issues.