Make searching example more lazy

[MatthijsBlom]

The old implementation was insufficiently lazy: it would insist on walking the entire list and therefore fail on

ouch = error "ouch"
ugh  = error "ugh"

-- >>> search [2,3] ( 1 : 2 : 3 : ouch : 5 : 6 : ugh )

Left folds aren't appropriate to this problem.