Remove TH1::Clone. Keep as before that a Clone on a TH1 object is done via TObject::Clone.
This reverts  patch http://root.cern.ch/gitweb?p=root.git;a=commit;h=63cc08cb780a2090045fc8ce1c03a2e48543a757

TProfileHelper now uses Copy instead of Clone in Profile::RebinAxis. This is more efficient and thread-safe