A fix for the broken implementation of HKHealhStore.deleteObjectsOfType in iOS 9.0 (see radar 22977320)

## HKHealthStore-DeleteObjects.swift
//
//  HKHealthStore-DeleteObjects.swift
//  HealthKitTest
//
//  Created by Ben Dodson on 06/10/2015.
//  Copyright © 2015 Dodo Apps. All rights reserved.
//

import Foundation
import HealthKit

extension HKHealthStore {

    func deleteSamplesOfType(sampleType: HKSampleType, predicate: NSPredicate, withCompletion completion: (success: Bool, count: Int, error: NSError?) -> Void) {

        let query = HKSampleQuery(sampleType: sampleType, predicate: predicate, limit: 0, sortDescriptors: nil) { (query, results, error) -> Void in

            if let _ = error {
                completion(success: false, count: 0, error: error)
                return
            }

            if let objects = results {
                if objects.count == 0 {
                    completion(success: true, count: 0, error: nil)
                } else {
                    self.deleteObjects(objects, withCompletion: { (success, error) -> Void in
                        completion(success: error == nil, count: objects.count, error: error)
                    })
                }
            } else {
                completion(success: true, count: 0, error: nil)
            }

        }
        self.executeQuery(query)
    }


}