Remove BUYCheckout from `storeCreditCard:completion:` callback.

Mobile Buy SDK/Mobile Buy SDK Tests/BUYIntegrationTest.m

@@ -220,12 +220,10 @@
 	__block id<BUYPaymentToken> token = nil;
 	
 	XCTestExpectation *expectation = [self expectationWithDescription:NSStringFromSelector(_cmd)];
-	[self.client storeCreditCard:creditCard checkout:_checkout completion:^(BUYCheckout *returnedCheckout, id<BUYPaymentToken> paymentToken, NSError *error) {
+	[self.client storeCreditCard:creditCard checkout:_checkout completion:^(id<BUYPaymentToken> paymentToken, NSError *error) {
 		XCTAssertNil(error);
 		XCTAssertNotNil(paymentToken);
-		XCTAssertNotNil(returnedCheckout);
 		
-		_checkout = returnedCheckout;
 		token = paymentToken;
 		[expectation fulfill];
 	}];

Mobile Buy SDK/Mobile Buy SDK/Data/BUYClient+Checkout.h

@@ -41,7 +41,7 @@ NS_ASSUME_NONNULL_BEGIN
  *  @param paymentToken  An opaque payment token type that wraps necessary credentials for payment
  *  @param error         Optional NSError
  */
-typedef void (^BUYDataCreditCardBlock)(BUYCheckout * _Nullable checkout, id<BUYPaymentToken> _Nullable paymentToken, NSError * _Nullable error);
+typedef void (^BUYDataCreditCardBlock)(id<BUYPaymentToken> _Nullable paymentToken, NSError * _Nullable error);
 
 /**
  *  Return block containing a BUYCheckout and/or an NSError

Mobile Buy SDK/Mobile Buy SDK/Data/BUYClient+Checkout.m

@@ -264,7 +264,7 @@
 		if (!error) {
 			token = [[BUYCreditCardToken alloc] initWithPaymentSessionID:json[@"id"]];
 		}
-		completion(checkout, token, error);
+		completion(token, error);
 	}];
 }