Comment 7 for bug 1333728

There is an issue when I test with update-manager 1:0.156.14.15 (sorry I didn't find the ubuntu bug for update-manager, so I add my comments here).

1. install ubuntu 12.04 on an amd64 machine
2. install the hwe lts-saucy stack
3. enable i386 support
4. install libgl1-mesa-glx-lts-saucy:i386
5. use update-manager to upgrade to the lts-trusty stack

Step 5 will fail with an error:

The following packages have unmet dependencies:

```
libgl1-mesa-glx-lts-trusty: Depends: libglapi-mesa-lts-trusty (= 10.1.3-0ubuntu0.1~precise1) but 10.1.3-0ubuntu0.1~precise1 is to be installed
                            Depends: libx11-6 (>= 2:1.4.99.1) but 2:1.4.99.1-0ubuntu2.2 is to be installed
                            Depends: libxdamage1 (>= 1:1.1) but 1:1.1.3-2build1 is to be installed
xserver-xorg-lts-trusty: Depends: xserver-xorg-core-lts-trusty (>= 2:1.11) but 2:1.15.1-0ubuntu2~precise1 is to be installed
```

The output of hwe-support-status --show-replacements is:
linux-generic-lts-trusty linux-image-generic-lts-trusty libgl1-mesa-glx-lts-trusty xserver-xorg-lts-trusty

However since there is libgl1-mesa-glx-lts-saucy:i386 installed we should also put libgl1-mesa-glx-lts-trusty:i386 into the replacements list.

In fact for each package in the replacements list we should check if it's also installed for other multiarch and add the lts-trusty replacement to the list too.