Change backup format so files are all in a single directory (no dir
hierarchies) and use an index file so we can save also ownership and
permission info for the restore (and eventually other data later on).
This patch adds a sysrestore module which allows ipa-server-install
code to backup any system state so that it can be restored again
with e.g. ipa-server-install --uninstall.
The idea is that any files ipa-server-install modifies gets backed
up to /var/cache/ipa/sysrestore/ while any "meta" state, like
whether a service is enabled with chkconfig, is saved to
/var/cache/ipa/sysrestore.state.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>