peer: allow msgStream goroutines to quit within the apply function
peer: allow msgStream goroutines to quit within the apply function

In this commit, we thread through the quit of the peer to the execution
of the apply function for a msgStream. This change ensures that if the
target is still processing the message, then the peer is able to exit
cleanly and not block insensately.

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