Updated create function to include error message with lcb_create failures.

Change-Id: Icdb8875d9717af9818e342a2b0b821642c8b9e6e
Reviewed-on: http://review.couchbase.org/29042
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>