Remove extra comma at end of enum list

C99-specific feature, and wasn't intentional in the first place.

Per buildfarm member mylodon

src/bin/pg_basebackup/walmethods.h

@@ -16,7 +16,7 @@ typedef enum
 {
 	CLOSE_NORMAL,
 	CLOSE_UNLINK,
-	CLOSE_NO_RENAME,
+	CLOSE_NO_RENAME
 }	WalCloseMethod;
 
 typedef struct WalWriteMethod WalWriteMethod;