os-downloader: Report duplicate os titles from downloader ui
This is done only on first load.
(org.gnome.Boxes:77099): Boxes-WARNING **: 09:08:57.091: os-downloader.vala:77: Duplicate OS titles from osinfo-db detected
1. Title: NetBSD 8.0 i686 (3 entries)
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.0/i386/installation/cdrom/boot-com.iso
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.0/images/NetBSD-8.0-i386.iso
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.0/i386/installation/cdrom/boot.iso
2. Title: NetBSD 8.0 x86_64 (3 entries)
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.0/amd64/installation/cdrom/boot.iso
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.0/amd64/installation/cdrom/boot-com.iso
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.0/images/NetBSD-8.0-amd64.iso
3. Title: NetBSD 8.1 Network Install i686 (netinst) (2 entries)
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.1/i386/installation/cdrom/boot.iso
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.1/i386/installation/cdrom/boot-com.iso
4. Title: NetBSD 8.1 Network Install x86_64 (netinst) (2 entries)
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.1/amd64/installation/cdrom/boot.iso
* https://archive.netbsd.org/pub/NetBSD-archive/NetBSD-8.1/amd64/installation/cdrom/boot-com.iso
5. Title: openSUSE Leap 15.4 x86_64 (Live) (4 entries)
* https://download.opensuse.org/distribution/leap/15.4/live/openSUSE-Leap-15.4-XFCE-Live-x86_64-Media.iso
* https://download.opensuse.org/distribution/leap/15.4/live/openSUSE-Leap-15.4-GNOME-Live-x86_64-Media.iso
* https://download.opensuse.org/distribution/leap/15.4/live/openSUSE-Leap-15.4-Rescue-CD-x86_64-Media.iso
* https://download.opensuse.org/distribution/leap/15.4/live/openSUSE-Leap-15.4-KDE-Live-x86_64-Media.iso
6. Title: openSUSE Leap 15.5 x86_64 (Live) (4 entries)
* https://download.opensuse.org/distribution/leap/15.5/live/openSUSE-Leap-15.5-GNOME-Live-x86_64-Media.iso
* https://download.opensuse.org/distribution/leap/15.5/live/openSUSE-Leap-15.5-KDE-Live-x86_64-Media.iso
* https://download.opensuse.org/distribution/leap/15.5/live/openSUSE-Leap-15.5-XFCE-Live-x86_64-Media.iso
* https://download.opensuse.org/distribution/leap/15.5/live/openSUSE-Leap-15.5-Rescue-CD-x86_64-Media.iso