DATAMONGO-1096 - RuntimeExceptions during debug query printing in MongoT...

When printing `DEBUG` logs for remove and update queries in `org.springframework.data.mongodb.core.MongoTemplate`, string value of queries should be obtained with `org.springframework.data.mongodb.core.query.SerializationUtils#serializeToJsonSafely` method. This protects us from RuntimeException's as mentioned in [DATAMONGO-495](https://jira.spring.io/browse/DATAMONGO-495)