KIS throwing error messages

### Affected Version

0.15

### Description

seeing this all over the logs of coordinator+overlord node for pretty much every data source

```
2019-07-23 19:26:13,086 ERROR o.a.d.m.IndexerSQLMetadataStorageCoordinator [qtp2120404899-84] Not updating metadata, existing state[KafkaDataSourceMetadata{SeekableStreamStartSequenceNumbers=SeekableStreamEndSequenceNumbers{stream='infraserver', partitionSequenceNumberMap={0=28736041678}}}] in metadata store doesn't match to the new start state[KafkaDataSourceMetadata{SeekableStreamStartSequenceNumbers=SeekableStreamStartSequenceNumbers{stream='infraserver', partitionSequenceNumberMap={0=28730133985}, exclusivePartitions=[]}}].

```

The report names IndexerSQLMetadataStorageCoordinator and the Kafka indexing service (KIS), with logs from coordinator and overlord nodes. Start by tracing that coordinator entry point and the KafkaDataSourceMetadata state transition. No test or acceptance criterion is provided, so confirm the cause and define the corrected behavior before implementing.

Written by the indexing model from the issue text.