【报Bug】[DCTZAssetCell requestBigImage] 调用sdk内自带的相册 崩溃

示例代码：

CrashDoctor Diagnosis: Attempted to dereference garbage pointer 0x16f8f9d4f.
2Thread 0 Crashed:
30 myAPP 0x00000001009e0cfc 32-[DCTZAssetCell requestBigImage]_block_invoke.26 + [DCTZAssetCell.m : 226]
41 myAPP 0x00000001009e0c58 32-[DCTZAssetCell requestBigImage]_block_invoke.26 + [DCTZAssetCell.m : 217]
52 libdispatch.dylib 0x00000001a89b413c _dispatch_call_block_and_release + [ : 32]
63 libdispatch.dylib 0x00000001a89b5dd4 _dispatch_client_callout + [ : 20]
74 libdispatch.dylib 0x00000001a89c45a4 _dispatch_main_queue_drain + [ : 988]
85 libdispatch.dylib 0x00000001a89c41b8 _dispatch_main_queue_callback_4CF + [ : 44]
96 CoreFoundation 0x00000001a0ae3710 CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE + [ : 16]
107 CoreFoundation 0x00000001a0ae0914 __CFRunLoopRun + [ : 1996]
118 CoreFoundation 0x00000001a0adfcd8 CFRunLoopRunSpecific + [ : 608]
129 GraphicsServices 0x00000001e59901a8 GSEventRunModal + [ : 164]
1310 UIKitCore 0x00000001a311890c -[UIApplication _run] + [ : 888]
1411 UIKitCore 0x00000001a31cc9d0 UIApplicationMain + [ : 340]
1512 UIKitCore 0x00000001a3346384 keypath_get_selector_hoverStyle + [ : 11024]
1613 myAPP 0x00000001008ef714 main + [AppDelegate.swift : 0]
1714 (null) 0x00000001c4191e4c 0x0 + 7584947788

操作步骤：

[DCTZAssetCell requestBigImage] 调用sdk内自带的相册 崩溃

预期结果：

[DCTZAssetCell requestBigImage] 调用sdk内自带的相册 崩溃

实际结果：

[DCTZAssetCell requestBigImage] 调用sdk内自带的相册 崩溃