If package installation has an error after the package is install (e.g.
when running tags), then there will be output on stderr and the fallback
regex will match; however, since pkg_add exited non-zero, changed is
never added as a key to the dictionary. As a result the code at the end
of main that checks if anything has changed raises a KeyError.
(cherry picked from commit 02d0e3d286)
Co-authored-by: Matthew Martin <phy1729@gmail.com>
afddbaa857