mncc: Remove what we believe to be a tautology from the MNCC code

Coverity pointed out that we use trans->subscr after a NULL check,
it is our believe that every transaction will have a subscriber.
Remove the check and add an assert before we are dispatching things.

Fixes: Coverity CID 1040740, CID 1040739
1 file changed
tree: 3746851ff5ebf0127fcd4c0fc56eb0c60656d176
  1. debian/
  2. hlrsync/
  3. linux-kernel/
  4. openbsc/
  5. wireshark/
  6. README