fix wrong sysctl

Signed-off-by: Sebastian Gumprich <sebastian.gumprich@t-systems.com>

Author: Sebastian Gumprich

controls/sysctl_spec.rb

@@ -314,7 +314,7 @@
   describe kernel_parameter('net.ipv6.conf.default.autoconf') do
     its(:value) { should eq 0 }
   end
-  describe kernel_parameter('net.ipv6.all.default.autoconf') do
+  describe kernel_parameter('net.ipv6.conf.all.autoconf') do
     its(:value) { should eq 0 }
   end
 end