bundlerepo: rename "bundle" arguments to "cgunpacker"
"bundle" was appropriate for the bundle1 days where a bundle
was a changegroup. In a bundle2 world, changegroup readers
are referred to as "changegroup unpackers."
Differential Revision: https://phab.mercurial-scm.org/D1383
#require docutils gettext
$ $TESTDIR/check-gendoc el
checking for parse errors