UpdateDeploymentService fails if project is nil

Not sure how this happened, but deployment.project was nil, leading to this exception: https://sentry.gitlab.net/gitlab/gitlabcom/issues/713271

@dosuken123 Do you have any idea how this could happen? In two examples I checked, they each had a project:

[ gprd ] production> Deployment.find(15900835).created_at
=> Fri, 12 Apr 2019 04:07:07 UTC +00:00
[ gprd ] production> Deployment.find(15900835).project.created_at
=> 2019-03-10 14:31:30 UTC

[ gprd ] production> Deployment.find(15900688).created_at
=> Fri, 12 Apr 2019 03:59:38 UTC +00:00
[ gprd ] production> Deployment.find(15900688).project.created_at
=> 2019-03-25 02:42:37 UTC

/cc: @dbalexandre