When there is an issue with SCM check out, the Build Now option disappears from
the job page and even if the link is fixed, it does n't show up.

Fo ex: I gave a wrong link for svn checkout. It failed and removed the build now
link.
Seems the idea is to disable it. But removing it completely from the job page
gives no clue about whats wrong or how we correct it and get it back to work.