[sugar-client] Handle unfinished yum transactions

[alsroot]

yum might be aborted in the middle of updating process and client updater needs to handle these situations.

[alsroot]

​http://git.sugarlabs.org/server/client/commit/a15d351594a9e580d4e10cfd3ee7461fbd7a175a
​http://git.sugarlabs.org/server/client/commit/03c7fc92630c53efb2dfb8a6ef2bb3c30da016b5

updater will try:

• to run yum-complete-transaction
• if it was failed, remove possible broken rpmdb
• try yum-complete-transaction once more
• if it was failed, clean up transactions

[sridhar]

yum-complete-transaction won't rescue the RPM if the installation was aborted when %post scripts are being executed. As far as the rpmdb is concerned, all the files are there. We need to be careful when creating RPMs to not rely too much on %post scripts, or have them short enough to minimise the chance of their execution being interrupted.

Also, we should inhibit system suspend while RPMs are being installed.

[alsroot]

Replying to sridhar:

yum-complete-transaction won't rescue the RPM if the installation was aborted when %post scripts are being executed. As far as the rpmdb is concerned, all the files are there. We need to be careful when creating RPMs to not rely too much on %post scripts, or have them short enough to minimise the chance of their execution being interrupted.

In fact, we might miss bunch of possible installation related issues. But not sure if it worth trying to solve all of them that might be reproducible in testing environment (since the picture w/ installed rpms should be the same on all of XOs, excluding cases when people attached new repositories and installed new packages manually).
(For the dbus related issues in sugar-client itself, it should return true for now, since dbus call is not critical in its %post).

Also, we should inhibit system suspend while RPMs are being installed.

I've created #3279. And closing this one since it was originally only about using yum-complete-transaction and it was fixed in SSK-1.1.