Use derive(Default) for HiveFormat (apache#348)

Signed-off-by: koushiro <[email protected]>

Author: koushiro

src/ast/mod.rs

@@ -1559,24 +1559,14 @@ pub enum HiveIOFormat {
     },
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Default)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct HiveFormat {
     pub row_format: Option<HiveRowFormat>,
     pub storage: Option<HiveIOFormat>,
     pub location: Option<String>,
 }
 
-impl Default for HiveFormat {
-    fn default() -> Self {
-        HiveFormat {
-            row_format: None,
-            location: None,
-            storage: None,
-        }
-    }
-}
-
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct SqlOption {