Added missing dictionaries for ROOT I/O

When storing a std::map, ROOT wants the first element of the stored
std::pair to be non-const for the dictionary declaration. If it
does not find the dictionary, it creates a dummy one but does it
at the wrong to for the threaded framework.
Merge pull request #2076 from Dr15Jones/addMissingDict

Misc cleanups -- Added missing dictionaries for ROOT I/O
Merge branch 'CMSSW_7_1_X' of https://github.com/cms-sw/cmssw into makeStaticThreadSafeInEventBase