Implemented skip_deserializing for enum

testing/tests/test_de.rs

@@ -37,7 +37,9 @@ enum Enum {
     Unit,
     Simple(i32),
     Seq(i32, i32, i32),
-    Map { a: i32, b: i32, c: i32 }
+    Map { a: i32, b: i32, c: i32 },
+    #[serde(skip_deserializing)]
+    Skipped,
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -805,6 +807,12 @@ declare_error_tests! {
         ],
         Error::UnknownVariant("Foo".to_owned()),
     }
+    test_enum_skipped_variant<Enum> {
+        &[
+            Token::EnumUnit("Enum", "Skipped"),
+        ],
+        Error::UnknownVariant("Skipped".to_owned()),
+    }
     test_struct_seq_too_long<Struct> {
         &[
             Token::SeqStart(Some(4)),