Well, I imagine the composition of those was down to the translator, seeing as Victor Hugo was French. The translator will have tried to render the idea, the meaning of Hugo's writing into English.
That doesn't matter too much for this question, though. Let's rewrite both sentences into more conventional modern word order and phrasing.
Love is the honey of the flower that is life.
Love is the honey for the flower that is life.
You see, the life/flower and love/honey combinations are metaphors. Life is represented by a flower, and love is represented by honey. So, let's get rid of the metaphorical association and just use the honey and flower:
The honey of the flower.
The honey for the flower.
Of is used genitively here, meaning it is the honey that comes from the flower (or belongs to it, or is associated with it closely - but we know that honey comes from flowers, albeit via bees). It makes more sense to talk about honey coming from a flower than it does to have honey being for a flower.
So, yes, number 1 is correct.
As to your rewriting, you can rewrite it that way as long as you're not showing it to someone who subscribes to the old "don't end a sentence with a preposition" thing. The phrasing is such as it is in your examples due to people trying to follow that rule. Personally, in this case (not always), I find the example more pleasing than the rewrite. It is harder to follow, though, and trying to always follow that rule can end up with very, very strange sentences and is, as is frequently noted, "the sort of nonsense up with which I will not put" (variants of that phrase are often attributed to Churchill, with no clear basis in fact, but the actual point is a good one).