Serialize Project.NameKey correctly

The ProjectNameKeySerializer() was not used for serialization
which introduced a diff in the serialized project names in the
mq payload when compared to the events produced by the
stream-events command.

Project names should consistantly been serialized as:

  {
  ...
  "project":"system/jenkins/ops"
  ...
  }

But ended up in some cases as:

  {
  ...
  "project":{"name":"system/jenkins/ops"}
  ...
  }

Change-Id: I9d00deae35f015ebd149b0260bd7dca79fc8fc94