bug#26607: 25.1; Installed packages get status 'dependency' after removing obsolete versions.

[Julian H]

When updating a package and then deleting the obsolete verion, the current 
installed packages don't have the status 'installed' afterwards but the status 
'dependency'.

How to replicate:
1. M-x package-list-packages
2. M-x package-menu-mark-obsolete-for-deletion
3. delete marked packages

Then the status of the currently installed version becomes
'dependency'.  For example, this might be problematic when using M-x
package-autoremove, because these packages would be deleted.