How to deal with missing import data

[axilleas]

Improve rake tasks to rerun certain tasks if data is missing.
Rerun when:

• Commits
  FedoraRpm.where(commits: nil)
• Versions
  Find fedorarpm ids with the following then rerun fedora:rpm:import:versions:
  RpmVersion.where(rpm_version: nil).inject([]) { |arr, rpm| arr << rpm.fedora_rpm_id; arr }
• Dependencies(?)
  Hard to know if something went wrong. We could just check for always picking the environment.
• Bugs(?)
  Hard to know if something went wrong. We could search the Bug list (once it gets implemented) and check for missing bugs.
• Builds(?)
  Hard to know if something went wrong