oasis: remove lwt.syntax from one package, because it infects others

All files within the directory get the syntax extension applied, even
if some are from other packages/libraries which use other syntax.

Signed-off-by: David Scott <dave.scott@citrix.com>
Async: use Monitor.finally to release the Mutex

Signed-off-by: David Scott <dave.scott@citrix.com>
Regenerate OASIS

Signed-off-by: David Scott <dave.scott@citrix.com>