Update systems.jl

Author: ChrisRackauckas

src/systems/systems.jl

@@ -22,7 +22,7 @@ function structural_simplify(
         allow_symbolic = true, allow_parameter = true, conservative = false, fully_determined = true,
         kwargs...)
     newsys′ = __structural_simplify(sys, io; simplify,
-        allow_symbolic = true, allow_parameter = true, conservative = false, fully_determined = true,
+        allow_symbolic, allow_parameter, conservative, fully_determined,
         kwargs...)
     if newsys′ isa Tuple
         @assert length(newsys′) == 2