Lower cooldown on Trist E

In light of the new 'combo' of Tristana's, I have a suggestion: lower the active cooldown on explosive charge.

But...also lower the damage by the same percentage.

The idea is that sometimes Tristana will need to switch targets, but if she already used up explosive charge on one champ she can't turn around and use it to power up her rocket jump on another all that quickly.

Now, I'm not saying it should be on a 5 second cooldown or anything, just shave off 1 or 2 seconds. And with a damage nerf to compensate, it shouldn't be a problem.