test: enable sparse-revlog for test-ssh-bundle1.t
We are about to enable sparse-revlog globally. To help with reviewing the
tests change, we isolate them in individual changesets.
Differential Revision: https://phab.mercurial-scm.org/D5335
cat >> $HGRCPATH <<EOF
[extensions]
narrow=
[ui]
ssh=python "$RUNTESTDIR/dummyssh"
[experimental]
changegroup3 = True
EOF