Ensure handles are closed when pipe disconnects

Ensure handles are closed when pipe disconnects

Fixes leaks where the pipe handles were not closed, preventing new
connections. Fixes the MONITOR_PIPE context leaking when its thread
is stopped.

Signed-off-by: Owen Smith <owen.smith@citrix.com>
Since error gotos are introduced, have them do the cleanup. The scope of
Pipe and Instance needs to be widened but it keeps the code neater overall.
Also removed the unnecessary newlines in the log messages.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>