Transaction: Fix NPE while reading db.properties file

Handle NPE while setting up data source in Transaction

- This occured as Transaction is called it would run the following which
  assumed db.properties file, which may not be in one's classpath;

        // Initialize with assumed db.properties file
        initDataSource("db.properties");
- So, while this would be logged in logs, this is ignored for DatabaseCreator's
  case. In DatabaseCreator we call initDataSource with full path anyway.

Signed-off-by: Rohit Yadav <bhaisaab@apache.org>
Transaction: Fix better debug message

Signed-off-by: Rohit Yadav <bhaisaab@apache.org>