minor change to checking dimensions in varInfo3 (#732)
minor change to checking dimensions in varInfo3 (#732)

* added check for invalid indexing that
returns more informative error msg than current
"index value of zero found"

* modify comment

* trivial change to trigger travis

nimble-dev/nimble,nimble-dev/nimble,nimble-dev/nimble,nimble-dev/nimble,nimble-dev/nimble