Removed unused member data

The clang compiler was warning about member data which were never
used.
Silence warning about hiding a virtual function

The clang compiler issued a warning that the declaration of result(...)
hid the version of that function from the base class. As the new
result(...) was being used and therefore was intended to be different from
the base class, issuing a 'using' declaration for the base class function
now silences the warning.
Merge pull request #5376 from Dr15Jones/clangFixRecoEgammaElectronIdentification

Clang fixes for RecoEgamma/ElectronIdentification