Pistol's blood overlay does not update its mirroring in realtime

[nashmuhandes]

Due to quirks with the pistol sprites (because it has actual sprites for the mirrored and non-mirrored version, instead of just being mirrored programmatically), when the player switches the pistol between left and right-handed, the blood overlay on the pistol doesn't update immediately (player has to select another weapon and then re-select the pistol for the blood overlay to properly update.