Workaround for bsc#1259311 - product conflict

[lslezak]

Problem

• Selecting the SLES product creates a conflict
• See more details in https://bugzilla.suse.com/show_bug.cgi?id=1259311

Solution

• Check if a *-release package is selected to install and if so then do not select the product to install.
• This is a temporary workaround, hopefully the problem will be solved on the libsolv side and we can remove it later.

Testing

• Tested manually, works fine

[imobachgs]

The workaround looks OK. However, that function is already rather long, so I would rather prefer to move most of this logic to a separate function.

At least, I would move the logic to find the release product to a separate one.

[imobachgs]

If we are sure that the workaround would be needed during a short period of time, then it is fine.