[antioch]: #2839, fixing ambigious overload by explicitly casting as Scalar type. Fixes a std::pow error on intel 11.1 on lonestar.
[antioch]: #2839, fixing ambigious overload by explicitly casting as Scalar type. Fixes a std::pow error on intel 11.1 on lonestar.

ddemidov/antioch,ddemidov/antioch,ddemidov/antioch,ddemidov/antioch