load updated record after update in order to adapt to change of juggler.3.22.1

[shenghu]

Description

The root cause is described in https://github.com/strongloop/loopback-connector-cassandra/issues/65. The solution is to load updated record from db.

Related issues

• connect to https://github.com/strongloop/loopback-connector-cassandra/issues/65

Checklist

• [x] New tests added or existing tests modified to cover all changes
• [x] Code conforms with the style guide

[shenghu]

The failure depends on https://github.com/strongloop/loopback-datasource-juggler/pull/1604 to be merged to juggler.

@bajtos @virkt25 @jannyHou please review.

[shenghu]

This is not needed any more as juggler fixed it.