wspr: Make Lookup requests made during server shutdown return an error.
PROBLEM:
When an RPC is made to a JS server after the tab has closed,
the RPC just hangs forever, since the Go Server's Listeners only close
after the server has completed Unmounting, and requests made after Stop
is called aren't handle by WSPR currently.
SOLUTION:
WSPR returns retryable errors when the the tab is closed, I am working on
an additional CL to support this in the Go Client retry code.
I also cleaned some minor things up while I was here.
Change-Id: I0d63d09b9ffd512d7462eb4a8d4d6b9154969665
6 files changed
