Fix: Model Message
Fix: Model Message

While importing messages to the projects, the series wasn't updating like in the add_message_from_mbox(). Added in the create to support the REST api.
Message-Id: <20180629071757.84632-1-shubhamjain7495@gmail.com>

Signed-off-by: Paolo Bonzini <69d3ebcf5ee4e7f05a50dc23cd96655b730804b4@redhat.com>
Reviewed-by: Fam Zheng <df9fd617995bad07eac70e27aa3fe5069270e3bd@redhat.com>

pvital/patchew,pvital/patchew,pvital/patchew,pvital/patchew