Change use of queryItems for iOS 7 compatibility
Change use of queryItems for iOS 7 compatibility

- See https://github.com/braintree/braintree_ios/issues/283

braintree/braintree_ios,apascual/braintree_ios,braintree/braintree_ios,billCTG/braintree_ios,apascual/braintree_ios,billCTG/braintree_ios,billCTG/braintree_ios,apascual/braintree_ios,billCTG/braintree_ios,braintree/braintree_ios,braintree/braintree_ios,billCTG/braintree_ios,apascual/braintree_ios