chore: Remove unused variables from kernel

when I build lean locally, I get a nice and warning-free build
experience with the exception of these two unused variables. They can
probably go?

src/kernel/inductive.cpp

@@ -614,7 +614,6 @@ class add_inductive_fn {
             d_idx++;
         }
         /* First, populate the field m_minors */
-        unsigned minor_idx = 1;
         d_idx = 0;
         for (inductive_type const & ind_type : m_ind_types) {
             name ind_type_name = ind_type.get_name();
@@ -666,7 +665,6 @@ class add_inductive_fn {
                 name minor_name = cnstr_name.replace_prefix(ind_type_name, name());
                 expr minor      = mk_local_decl(minor_name, minor_ty);
                 m_rec_infos[d_idx].m_minors.push_back(minor);
-                minor_idx++;
             }
             d_idx++;
         }

src/library/compiler/csimp.cpp

@@ -302,12 +302,10 @@ class csimp_fn {
     }
 
     expr get_minor_body(expr e, buffer<expr> & xs) {
-        unsigned i = 0;
         while (is_lambda(e)) {
             expr d = instantiate_rev(binding_domain(e), xs.size(), xs.data());
             expr x = m_lctx.mk_local_decl(ngen(), binding_name(e), d, binding_info(e));
             xs.push_back(x);
-            i++;
             e  = binding_body(e);
         }
         return instantiate_rev(e, xs.size(), xs.data());