Explicitly importing MobileCoreServices.

Fixes failing test

AFNetworking/AFURLRequestSerialization.m

@@ -22,6 +22,12 @@
 
 #import "AFURLRequestSerialization.h"
 
+#if __IPHONE_OS_VERSION_MIN_REQUIRED
+#import <MobileCoreServices/MobileCoreServices.h>
+#else
+#import <CoreServices/CoreServices.h>
+#endif
+
 extern NSString * const AFNetworkingErrorDomain;
 
 typedef NSString * (^AFQueryStringSerializationBlock)(NSURLRequest *request, NSDictionary *parameters, NSError *__autoreleasing *error);