.hash file of runtime created config file is not deleted

When an object in a static config file is modified, in addition to a runtime .cnf file, a .cnf.hash file will also be created. The latter is used for detecting at next MaxScale start, whether the object in the static config file has been modified after the runtime change was made, so that an appropriate warning can be displayed.

If a runtime change that restores the object to the state in the static config file is made, the runtime created .cnf file will be deleted, but the .cnf.hash file will not.