PUT requests to scope policies cannot change the matchingPolicy

[federicaagostini]

When one wants to modify a scope policy, a request such as

PUT /iam/scope_policies/{ID}

cannot change the matchingPolicy field, while POST /iam/scope_policies works as expected.

Possible affected lines are https://github.com/indigo-iam/iam/blob/master/iam-persistence/src/main/java/it/infn/mw/iam/persistence/model/IamScopePolicy.java#L215-L223.