Bug 1373 - Fixed NullPointerException on incorrect input

 - now throws IllegalArgumentException. This is just logged and pushed into Future, the Future delegates the information further to upper ODL layers

Change-Id: I64ac1e4904e8837ab5b26572235bdaf5fac984da
Signed-off-by: Michal Polkorab <michal.polkorab@pantheon.sk>