Fix strerror unit test

Should reflect the new LCB_MAX_ERROR value

Change-Id: Ibac2fc53737d48d8fdf6042f247e2db5999214ed
Reviewed-on: http://review.couchbase.org/29923
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>