Fix harmless compiler warnings.

FossilOrigin-Name: a7e5fcd66659750eb2f4675082df324e7cf35427

src/vdbeaux.c

@@ -2835,7 +2835,7 @@ static u64 floatSwap(u64 in){
 ** of bytes in the zero-filled tail is included in the return value only
 ** if those bytes were zeroed in buf[].
 */ 
-u32 sqlite3VdbeSerialPut(u8 *buf, Mem *pMem, u32 serial_type, int file_format){
+u32 sqlite3VdbeSerialPut(u8 *buf, Mem *pMem, u32 serial_type){
   u32 len;
 
   /* Integer and Real */