Merge pull request #58 from thescouser89/errata_temp_fix

Temporary work-around to errata nvrs getting out of sync
SCM URL checks

- If git_url is unfilled when package is flipped to finished, then
  autofill that data
- If it is not filled, then check if the mead build scm_url is the same as the
  one in ETT
- Disable editing the git_url if the package is flipped to finished state
Merge pull request #59 from thescouser89/scm_url_work

SCM URL checks
Add advisory field to Tasks and other stuff

Other stuff:
- Since cron job now sends the advisory to ETT, we don't have to hard-code to
  which task the packages arriving to ETT belong to. From the advisory, we'll
  try to find the task that has that advisory
Merge pull request #60 from thescouser89/advisory

Add advisory field to Tasks and other stuff