[Durability]: SyncWrite abort increments the 'ops_delete' counter in vbucket-details stats wrongly

Build: 6.5.0-4908

Scenario:

1. 2 node cluster, couchbase bucket
2. Stop replica memcached
3. Perform sync_write on active vbucket with timeout=5 seconds

Observation:

After step #3, sync_write fails with 'DurabilityAmbiguousException'. After this, cbstats vbucket-details' ops_delete is also incremented by 1.

Expected behavior:

Since there is no delete operation involved this counter should not change.