Coverdale/PageEntertainment Weekly April 2, 1993 FEW REASONS to consider buying the first collaboration by ex-Led Zeppelin guitarist Jimmy Page and ex-Whitesnake singer David Coverdale: (1) You've worn out the CD grooves on your Zeppelin boxed set, so you'll settle for Page and Robert Plant manque Coverdale's attempt to re-create the monolithic Led Zep sound. As they used to say on TV--not the real thing, but an incredible simulation! (2) As Zep simulations go, it is pret