C++: fix local types and members

It fixes code model when we have local type which contains a member
of other type, e.g.:
struct OtherType { int otherTypeMember; };
void foo()
{
    struct LocalType
    {
        int localTypeMember;
        OtherType ot;
    };

    LocalType lt;
    lt.ot.//no code completion
}

Change-Id: I018f492a6c48bfcbba0ef376ef005825e2b13f35
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>