bugfix: search for tags failed, if only one transaction with the given parameters was present

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

accounting/src/main/java/de/srsoftware/umbrella/accounting/SqliteDb.java

@@ -183,7 +183,7 @@ public class SqliteDb extends BaseDb implements AccountDb {
 				}
 			}
 			rs.close();
-			return set;
+			return set == null ? transactionTags : set;
 		} catch (SQLException e){
 			throw failedToLoadMembers(accountId);
 		}