Fix duplicate resource (describe.one)

controls/1_4_secure_boot_settings.rb

@@ -30,6 +30,7 @@
   describe.one do
     grub_conf.locations.each do |f|
       describe file(f) do
+        next unless file(f).exist?
         it { should exist }
         it { should_not be_readable.by 'group' }
         it { should_not be_writable.by 'group' }
@@ -55,6 +56,7 @@
   describe.one do
     grub_conf.locations.each do |f|
       describe file(f) do
+        next unless file(f).exist?
         its(:content) { should match(/^set superusers/) }
         its(:content) { should match(/^password/) }
       end

controls/1_6_mandatory_access_control.rb

@@ -166,6 +166,7 @@
   describe.one do
     grub_conf.locations.each do |f|
       describe file(f) do
+        next unless file(f).exist?
         its('content') { should_not match /apparmor=0/ }
       end
     end

controls/4_1_configure_system_accounting_auditd.rb

@@ -127,6 +127,7 @@
   describe.one do
     grub_conf.locations.each do |f|
       describe file(f) do
+        next unless file(f).exist?
         its('content') { should match(/audit=1/) }
       end
     end