fix verify_mok()
fix verify_mok()

() Fix the return value semantics. If the MokList doesn't
exist, we are OK. If the MokList was compromised but we
were able to erase it, that is OK too. Only if the list
can't be nuked do we return an error.

() Fix use of potentially uninitialized attribute variable

() Actually use the return value when called from verify_buffer.

Change-Id: If16df21d79c52a1726928df96d133390cde4cb7e
Signed-off-by: Andrew Boie <aab045b28152628be6af0e556050d0381fd0a34d@intel.com>

CyanogenMod/android_external_uefi_shim,android-ia/platform_external_uefi_shim,CyanogenMod/android_external_uefi_shim,android-ia/platform_external_uefi_shim,CyanogenMod/android_external_uefi_shim,android-ia/platform_external_uefi_shim