Do not clear validationinterface entries being executed
Do not clear validationinterface entries being executed

The previous code for MainSignalsInstance::Clear would decrement the reference
count of every interface, including ones that were already Unregister()ed but
still being executed.


Former-commit-id: 1965e1e4151283f1e7e6644a02ae2b34ba8f145c
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin