bundle-spec: properly parse boolean configuration as boolean
Before this changesets "v2;revbranchcache=no" would actually request the
addition for a revbranchcache part as the non-empty string `"0"` is `True`
#require docutils gettext
Error: the current ro localization has some rst defects exposed by
moving pager to core. These two warnings about references are expected
until the localization is corrected.
$ $TESTDIR/check-gendoc ro
checking for parse errors
gendoc.txt:58: (WARNING/2) Inline interpreted text or phrase reference start-string without end-string.
gendoc.txt:58: (WARNING/2) Inline interpreted text or phrase reference start-string without end-string.