osx: install bash and zsh completions by default
The zsh location appears to be on the default $fpath for zsh. bash, on
the other hand, appears to have no default location for completion
scripts, so we follow the lead of Apple's Git distribution and select
a semi-arbitrary place in /usr/local for the file.
#require docutils gettext
$ $TESTDIR/check-gendoc fr
checking for parse errors