lntest/itest: prevent direct connection within testNodeAnnouncement
lntest/itest: prevent direct connection within testNodeAnnouncement

Alice and Dave don't need to be connected in order to receive the node
announcement as we assume that she can receive it from Bob because they
are connected at the beginning of every test.

aakselrod/lnd,aakselrod/lnd,LightningNetwork/lnd,LightningNetwork/lnd