Fixes to bug 935031

This merge request contains two patches, both concerning black konsole display after loading previous session

1. First one only deals with the blackness (and resulting crash, which wasn't mentioned in the bug report, but can happen after you add a tab and close it). I will surely be submitting this one upstream.
2. Second actually goes a bit further by reinstating teh code for loading the old session format. I'm not sure if this is for upstream, however, we can have it in Debian to allow users to migrate their sessions when they upgrade (eg. in stable).