Add gen-version

commit 739f9b1965863a116e9ef1e77bced981d5a4a006
Author: Richard Marko <rmarko@fedoraproject.org>
Date:   Thu Nov 6 12:39:41 2014 +0100

    Add gen-version
    
    Similar to the rest of ABRT projects, faf version now contains
    number of commits after the last tag and short
    commit hash of the last commit built e.g.:
    
    faf-0.12.20.g0af7-1.fc20.noarch.rpm
    
    Signed-off-by: Richard Marko <rmarko@fedoraproject.org>