fix for icc compiler: added the missing pat:: namespace

This should fix the following compilation errors for ICC builds
```DataFormats/PatCandidates/interface/Jet.h(482): error: no instance of overloaded function "reco::operator<<" matches the specified type
        friend std::ostream& reco::operator<<(std::ostream& out, const Jet& obj);```
```DataFormats/PatCandidates/interface/Muon.h(238): error: no instance of overloaded function "reco::operator<<" matches the specified type
        friend std::ostream& reco::operator<<(std::ostream& out, const Muon& obj);```