And whether he deliberately wanted Severus to die, simply did not care about the risk to Severus, or merely failed to even consider whether he ought to mention it, is irrelevant to the outcome. He consciously chose a course of action that put Severus at even greater risk of death and failed to give him information that could have helped him save his life, even though any person of average intelligence could reasonably be expected to see that this course of action would put Severus' life at risk. Whether intentionally or not, he set up Severus' death and failed to so much as say 'oh, by the way, Voldemort might have a new reason to kill you in the near future' or 'you know this wand of mine? Voldemort thinks it is the Elder Wand, and he's going to want it after you kill me.'
And ignorance about the wand's nature was no defense against Voldemort - as we *quite clearly see* in the books. That's the entire point maidofkent and others are trying to make. He doesn't know about the wand, and therefore does not suspect when Voldemort calls him that Voldemort intends to murder him for it! KNOWING about the wand would have been more of a defense, in that he could have acted with knowledge of Voldemort's likely plans and so have had a better chance of escaping with his life.