Ephemeral buckets: OOM fail-delete does not fail

Build 2466. I am running a test which configures an ephemeral bucket as "fail when full", fills up memory and continues to do sets. I expect that the sets will fail but using both the memcache and SDK python client they continue to succeed based on the return code. The ops/sec is around 100 sets/sec but the number of items stat does not increase. The OOM stats remains 0.

The test is:

./testrunner -i 1node.ini  -t eviction.evictionkv.EphemeralBucketsOOM.test_ephemeral_bucket_no_deletions,replicas=0,bucket_size=100,items=1000,vbuckets=1024,bucket_type=ephemeral