reftable: remove unnecessary curly braces in reftable/tree.c

According to Documentation/CodingGuidelines, single-line control-flow
statements must omit curly braces (except for some special cases).
Make reftable/tree.c adhere to this guideline.

Mentored-by: Patrick Steinhardt <[email protected]>
Mentored-by: Christian Couder <[email protected]>
Signed-off-by: Chandra Pratap <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Chandra Pratap

reftable/tree.c

@@ -39,25 +39,20 @@ struct tree_node *tree_search(void *key, struct tree_node **rootp,
 void infix_walk(struct tree_node *t, void (*action)(void *arg, void *key),
 		void *arg)
 {
-	if (t->left) {
+	if (t->left)
 		infix_walk(t->left, action, arg);
-	}
 	action(arg, t->key);
-	if (t->right) {
+	if (t->right)
 		infix_walk(t->right, action, arg);
-	}
 }
 
 void tree_free(struct tree_node *t)
 {
-	if (!t) {
+	if (!t)
 		return;
-	}
-	if (t->left) {
+	if (t->left)
 		tree_free(t->left);
-	}
-	if (t->right) {
+	if (t->right)
 		tree_free(t->right);
-	}
 	reftable_free(t);
 }