Embed consistency check results in ChangeInfo result

We would like to provide a way for bulk consistency checks, which
wouldn't fit very well with a single CheckResult entity, as we need to
associate each change with its list of problem messages. A cleaner way
to achieve this is to embed the problems in the change itself.

Change-Id: Idf3f39ce2423816b974643c71ab28d2075408e81
6 files changed