There may be two different things going on here. The bug was fixed in upstart 1.11, some time ago.
On the other hand, I noticed (as you did) in the last few days that my new files were getting a umask of 0027, contrary to the upstart profile I had installed. Because of the timing, I suspect the GNOME 3.10 upgrade (which I received via the GNOME3-team PPA) somehow caused the workaround to stop working.
Since it was possible to install upstart 1.11 from trusty without pulling in other dependencies, I did so, which cured the problem, as the bug is fixed there and the workaround no longer needed.
There may be two different things going on here. The bug was fixed in upstart 1.11, some time ago.
On the other hand, I noticed (as you did) in the last few days that my new files were getting a umask of 0027, contrary to the upstart profile I had installed. Because of the timing, I suspect the GNOME 3.10 upgrade (which I received via the GNOME3-team PPA) somehow caused the workaround to stop working.
Since it was possible to install upstart 1.11 from trusty without pulling in other dependencies, I did so, which cured the problem, as the bug is fixed there and the workaround no longer needed.