Resolve typedefs in unit test

Unit test CondCore/ORA/test/testORA_7.cc will fail in ROOT6 after the CMS specific patch to ROOT (the TType class) is phased out, for two different reasons.
This ROOT6 specific pull request fixes both of these reasons.
1) The test should remove typedefs from function return types by calling FunctionWithDict::finalReturnType() instead of FunctionWithDict::typeOf().
2) A missing dictionary for std::vector<short>::iterator is added to the XML selection file.
Please merge this request as soon as convenient.