The status UNKNOWN in the UI is sometimes inappropriate

[itleigns]

What happened: If we create an event whose startFrom is ~commit in a pipeline which does not have a job with ~commit in requires, the status in the UI becomes UNKNOWN.

What you expected to happen: We want the status to show that there is no job to start. The status is not good to be UNKNOWN when it is working properly. How to reproduce it:

[jithine]

Perhaps we can simply say, "No Builds"

[tkyi]

Just need to change some defaults in the UI and minor template logic: https://github.com/screwdriver-cd/ui/blob/master/app/event/model.js#L29