Fixes #2614

Results from the query should be skipped if they are already in the
ISet distinction thus if distinction.Add is false. Currently, they are
only added if they have been there before.

Signed-off-by: csharper2010

Author: wvopt

src/NHibernate/Async/Engine/Query/HQLQueryPlan.cs

@@ -78,7 +78,7 @@ public async Task PerformListAsync(QueryParameters queryParameters, ISessionImpl
 					for (int x = 0; x < size; x++)
 					{
 						object result = tmp[x];
-						if (distinction.Add(result))
+						if (!distinction.Add(result))
 						{
 							continue;
 						}

src/NHibernate/Engine/Query/HQLQueryPlan.cs

@@ -128,7 +128,7 @@ public void PerformList(QueryParameters queryParameters, ISessionImplementor ses
 					for (int x = 0; x < size; x++)
 					{
 						object result = tmp[x];
-						if (distinction.Add(result))
+						if (!distinction.Add(result))
 						{
 							continue;
 						}