provisioner: remove repos before adding ours

[bmwiedemann]

to make it easier to re-run crowbar_register in case of errors

[jsuchome]

can't users have some custom repos? (on the other hand, we're doing this as well during the upgrade)

[bmwiedemann]

They could have custom repos, but then those repo names could collide with crowbar's too ... and if they are not SUSE repos, packages could collide which we do not want to support.

[nicolasbock]

But if the customer wants to add custom repositories, when would they need to add them? Is crowbar_register run only when you allocate a new node?

[bmwiedemann]

it only runs once.

an alternative would be to do zypper rr $repo before adding it, so we only drop repos with our names.

[jsuchome]

zypper rr $repo sounds indeed safer, however as pointed out in the case of upgrade, we actually do remove all present repos at some point ... so I think it does not hurt in this time, esp. when the user can add extra repos after runing crowbar_register