Public methods defined on the object was being delegated to the decorator even though it was overridden by a private method.
## Testing
1. Create a simple PORO with a public method
```ruby
class Job
def location
Struct.new(:id) { }
end
end
```
1. Create a decorator and override the public method with a private
```ruby
class JobDecorator < Draper::Decorator
delegate_all
private
def location
LocationDecorator.new(object.location)
end
end
```
3. It should raise an exception when calling `.location` from the decorator
```ruby
[9] pry(main)> JobDecorator.decorate(Job.new).location
NoMethodError: private method `location' called for #<JobDecorator:0x0000559f113ba118>
```
## References
* Issue #771
d44c86f1e5