Add the revert functionality to firstaidkit.

This introduces new requirements to the plugins.

1. If a plugin wants to be revertable it must implement the revert function.
   This function will be accessible from the plugins top most namespace.  The
   same place where get_plugin is.

2. For the plugin's backend directory to be easily found, the plugin must
   give the backend its module name as an id.  In this way when the user
   specifies in the revert command line plugin 'x', the revert class will
   go to the backup directory in search for a directory called the same
   way as the module of 'x'.

3. If the plugin developer does not want to use the system of backup dir
   naming, there is a second way how to specify the backup dir.  The
   plugin must specify a function getBackupId(), that will return the id
   of the backup space that can be used for the backup dir search.

Backup spaces that fail to comply with these directive will be ignored.

1 files changed, 2 insertions, 0 deletions

diff --git a/pyfirstaidkit/configuration.py b/pyfirstaidkit/configuration.py
index b25bf1b..01f4ac7 100644
--- a/pyfirstaidkit/configuration.py
+++ b/pyfirstaidkit/configuration.py
@@ -46,6 +46,8 @@ def createDefaultConfig(config):
     config.backup.method = "file"
     config.backup.rootpath = "/tmp/fakbackup"
     config.backup.fullpath = ""
+    config.revert.all = "False"
+    config.revert.dir = ""
 
     # Setup a sane default root directory.
     if os.path.isdir("/mnt/sysimage"):