Just change
function CrowbarProjectile::onCollision(%this,%obj,%col,%fade,%pos,%normal)
to
function CrowbarProjectile::onCollision(%this,%obj,%col,%fade,%pos,%normal, %rot)
and the line after it from
parent::onCollision(%this,%obj,%col,%fade,%pos,%normal);
to
parent::onCollision(%this,%obj,%col,%fade,%pos,%normal, %rot);