This update fixes the following issues for argus-client:
- Changed the licence in specfile to GPL-2.0+ and GPL-2.0, since there are no other licences in 3.0.6.
- update to 3.0.6 - bnc#739260 - Multiple licensing problems with argus-client 3.0.0
- remove obsolete argus-clients-3.0.0-leak-fix.patch.