PEKKA needs one more little fix

Removing the bonus damage from teslas has almost made PEKKAs relevant again when combined with haste spells, but I suggest increasing the attack speed slightly while keeping DPS the same. The reason is that skeleton traps demolish PEKKAs just as bad as the old tesla bonus damage did, maybe worse. Watching PEKKAs slowly hack away at skeletons one at a time while getting pounded by half the defenses in the base is ridiculous. Valks kill all the skeletons in a fraction of a second. This tweak will make PEKKAs versus mass valks a more interesting choice as it should be.