fix krylov verbosity

Author: jClugstor

src/iterative_wrappers.jl

@@ -284,7 +284,7 @@ function SciMLBase.solve!(cache::LinearCache, alg::KrylovJL; kwargs...)
         cache.cacheval
     end
 
-    krylovJL_verbose = verbosity_to_int(verbose.numerical.KrylovJL_verbosity)
+    krylovJL_verbose = isnothing(verbose.numerical) ? 0 : verbosity_to_int(verbose.numerical.KrylovJL_verbosity)
 
     args = (cacheval, cache.A, cache.b)
     kwargs = (atol = atol, rtol, itmax, verbose = krylovJL_verbose,