CCBC-255 Expose LCB_MAX_ERROR to allow user-defined codes

Change-Id: I335411a6f90c0b6e6215e249c6024471575b3fbe
Reviewed-on: http://review.couchbase.org/29920
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>