Do not disable vfat by default

On UEFI-systems the boot-partition is FAT by default (see [here](https://wiki.archlinux.org/index.php/Unified_Extensible_Firmware_Interface/System_partition)).

If we disable vfat, these systems become unbootable. This has already bitten some users using ansible-os-hardening (dev-sec/ansible-collection-hardening#162, dev-sec/ansible-collection-hardening#145).

Therefore I propose we do not check for a disabled vfat filesystem as vfat is often used on newer systems.

controls/os_spec.rb

@@ -210,7 +210,6 @@
     its(:content) { should match 'install hfsplus /bin/true' }
     its(:content) { should match 'install squashfs /bin/true' }
     its(:content) { should match 'install udf /bin/true' }
-    its(:content) { should match 'install vfat /bin/true' }
   end
 end