AnonDialer will now return a "not found" error if the pipe is not found
before the timeout is reached. If the pipe exists but the timeout is
reached while attempting to connect, the timeout error will still be
returned.
This will allow the error handling logic to work properly when
connecting to the shim log pipe. An error message is only logged if the
error is not "not found", so now log noise from log pipes that were
never intended to be created by the shim will be hidden.
This change also cleans up the control flow for AnonDialer on Windows.
The new code should be more easily readable, but the only semantic
change is the error return value change.
Signed-off-by: Kevin Parsons <kevpar@microsoft.com>