Staging: batman-adv: adapting source version to revised versioning scheme

The new versioning scheme looks like this:
* the trunk will simply be named "devel" followed by a revision number
* the upcoming release branch will be "maint" followed by a revision
  number
* the releases will carry their respective names (e.g. 2010.0.0)

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>