Adding repositories that could not be probed in disabled state

- During upgrade, the old repositories are read from the system
- The upgrade offers them to the user and they can either remove them, add them enabled or add them disabled
- Enabled repositories are used during the upgrade
- Disabled aren't used but they can be re-enabled again later
- In bnc#779396 user has a configured network but it doesn't work (what we can't detect) so user is allowed to use remote repository as enabled but because probing the repository fails, it's thrown away. This patch takes such repository and adds it as disabled so it's not lost.