rfkill: set release to version suffix

If version suffix is not set, then compilation try look it from
git version. This can cause problems because rfkill is not from git,
but it it compile inside distribution git directory.

Signed-off-by: Kalle Lampila <kalle.lampila@ixonos.com>
Merge pull request #8 from kallelampila/master

rfkill: set release to version suffix