In summary, the problem here is twofold. 1) The progress bar dialog window was not set up to properly translate its title 2) The glade tool I used to update the .glade files inserted a bunch of contexts for the strings that breaks translations. This bug corrects both of these issues.
Just kidding about #2, that was fixed in a previous commit in Spacewalk master. This bug is only addressing #1, the progress dialog translations.
Committing as 3058cc7849afd78321366e47cdf569c8a64d3cab
Marking bug as ON_QA since tonight's build of Spacewalk nightly is a release candidate for Spacewalk 1.9.
Spacewalk 1.9 has been released. https://fedorahosted.org/spacewalk/wiki/ReleaseNotes19