NCBC-703: When an operation timesout ensure that an NRE is not thrown

Change-Id: Iba4be3d23a1d416b2c64a4d0c04d22b3ec0c9011
Reviewed-on: http://review.couchbase.org/42555
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Jeffry Morris <jeffrymorris@gmail.com>
Tested-by: Jeffry Morris <jeffrymorris@gmail.com>