The configuration files /etc/sysconfig/bootloader and
/etc/default/grub needs to be created/updated with the
relevant values regarding the bootloader setup done by
kiwi. This Fixes#226
The method target_supports_extended_attributes() checks if the
sync target directory supports extended filesystem attributes.
The method is called on sync_data() and will remove the -X / -A
options if provided. A warning message is issued to the caller
if the rsync option list has changed because of the underlaying
filesystem limitations
