Comment 4 for bug 1693900

Because of this bug ppa-purge misbehaves (Bug #1514839). Should one inspect the output of apt-get for '^Err:' (from standard output) or even '^W:' (from standard error) to determine, if it updated the repositories or not? Besides the output of `apt-get update` varies between versions in supported Ubuntu releases: In Ubuntu 14.04 it does not print ':' after 'Err', but ' ', instead.