Remove SkAutoDescriptor move ctor

Change-Id: I290a3bcac74e64c8aa11e7b1664cbb54111541eb
Reviewed-on: https://skia-review.googlesource.com/145422
Auto-Submit: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>

src/core/SkDescriptor.h

@@ -158,6 +158,8 @@ public:
 
     SkDescriptor* getDesc() const { SkASSERT(fDesc); return fDesc; }
 private:
+    SkAutoDescriptor(SkAutoDescriptor&&) = delete;
+    SkAutoDescriptor& operator =(SkAutoDescriptor&&) = delete;
     void free() {
         if (fDesc != (SkDescriptor*)(void*)fStorage) {
             delete fDesc;