Removed unused member data

Removed unused member data flagged by clang.
Fixed incorrect header guard

Problem found by clang.
clang required const global object to have a default constructor
Fixed clang compiler warnings

Removed unused member variable
Fixed forward declartion to match type declaration
Commented out variable self assignment

clang complained about variables being assigned to themselves. The
code has been commented out and a comment asking if the self assignment
was a mistake or intended was added.
Merge pull request #4044 from Dr15Jones/clangFixRecoMuonMuonSeedGenerator

Clang fixes for RecoMuon/MuonSeedGenerator