LoKi::Dicts::CutValOps : add few more overloads for `__switch__` method (@ibelyaev)

Cherry-picked from !1386 (merged) on run2-patches

• [2018-07-02 00:14] Validation started with lhcb-head#1905
• [2018-07-02 00:14] Validation started with lhcb-lcg-dev3#573
• [2018-07-02 00:16] Validation started with lhcb-tdr-test#201
• [2018-07-02 00:16] Validation started with lhcb-lcg-dev4#573
• [2018-07-02 00:17] Validation started with lhcb-gaudi-head#1918

merged

mentioned in commit a20494f3